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      1 //===--- CGDebugInfo.cpp - Emit Debug Information for a Module ------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This coordinates the debug information generation while generating code.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "CGDebugInfo.h"
     15 #include "CGBlocks.h"
     16 #include "CGRecordLayout.h"
     17 #include "CGCXXABI.h"
     18 #include "CGObjCRuntime.h"
     19 #include "CodeGenFunction.h"
     20 #include "CodeGenModule.h"
     21 #include "clang/AST/ASTContext.h"
     22 #include "clang/AST/DeclFriend.h"
     23 #include "clang/AST/DeclObjC.h"
     24 #include "clang/AST/DeclTemplate.h"
     25 #include "clang/AST/Expr.h"
     26 #include "clang/AST/RecordLayout.h"
     27 #include "clang/Basic/FileManager.h"
     28 #include "clang/Basic/SourceManager.h"
     29 #include "clang/Basic/Version.h"
     30 #include "clang/Frontend/CodeGenOptions.h"
     31 #include "clang/Lex/HeaderSearchOptions.h"
     32 #include "clang/Lex/ModuleMap.h"
     33 #include "clang/Lex/PreprocessorOptions.h"
     34 #include "llvm/ADT/SmallVector.h"
     35 #include "llvm/ADT/StringExtras.h"
     36 #include "llvm/IR/Constants.h"
     37 #include "llvm/IR/DataLayout.h"
     38 #include "llvm/IR/DerivedTypes.h"
     39 #include "llvm/IR/Instructions.h"
     40 #include "llvm/IR/Intrinsics.h"
     41 #include "llvm/IR/Module.h"
     42 #include "llvm/Support/FileSystem.h"
     43 #include "llvm/Support/Path.h"
     44 using namespace clang;
     45 using namespace clang::CodeGen;
     46 
     47 CGDebugInfo::CGDebugInfo(CodeGenModule &CGM)
     48     : CGM(CGM), DebugKind(CGM.getCodeGenOpts().getDebugInfo()),
     49       DebugTypeExtRefs(CGM.getCodeGenOpts().DebugTypeExtRefs),
     50       DBuilder(CGM.getModule()) {
     51   for (const auto &KV : CGM.getCodeGenOpts().DebugPrefixMap)
     52     DebugPrefixMap[KV.first] = KV.second;
     53   CreateCompileUnit();
     54 }
     55 
     56 CGDebugInfo::~CGDebugInfo() {
     57   assert(LexicalBlockStack.empty() &&
     58          "Region stack mismatch, stack not empty!");
     59 }
     60 
     61 ApplyDebugLocation::ApplyDebugLocation(CodeGenFunction &CGF,
     62                                        SourceLocation TemporaryLocation)
     63     : CGF(&CGF) {
     64   init(TemporaryLocation);
     65 }
     66 
     67 ApplyDebugLocation::ApplyDebugLocation(CodeGenFunction &CGF,
     68                                        bool DefaultToEmpty,
     69                                        SourceLocation TemporaryLocation)
     70     : CGF(&CGF) {
     71   init(TemporaryLocation, DefaultToEmpty);
     72 }
     73 
     74 void ApplyDebugLocation::init(SourceLocation TemporaryLocation,
     75                               bool DefaultToEmpty) {
     76   auto *DI = CGF->getDebugInfo();
     77   if (!DI) {
     78     CGF = nullptr;
     79     return;
     80   }
     81 
     82   OriginalLocation = CGF->Builder.getCurrentDebugLocation();
     83   if (TemporaryLocation.isValid()) {
     84     DI->EmitLocation(CGF->Builder, TemporaryLocation);
     85     return;
     86   }
     87 
     88   if (DefaultToEmpty) {
     89     CGF->Builder.SetCurrentDebugLocation(llvm::DebugLoc());
     90     return;
     91   }
     92 
     93   // Construct a location that has a valid scope, but no line info.
     94   assert(!DI->LexicalBlockStack.empty());
     95   CGF->Builder.SetCurrentDebugLocation(
     96       llvm::DebugLoc::get(0, 0, DI->LexicalBlockStack.back()));
     97 }
     98 
     99 ApplyDebugLocation::ApplyDebugLocation(CodeGenFunction &CGF, const Expr *E)
    100     : CGF(&CGF) {
    101   init(E->getExprLoc());
    102 }
    103 
    104 ApplyDebugLocation::ApplyDebugLocation(CodeGenFunction &CGF, llvm::DebugLoc Loc)
    105     : CGF(&CGF) {
    106   if (!CGF.getDebugInfo()) {
    107     this->CGF = nullptr;
    108     return;
    109   }
    110   OriginalLocation = CGF.Builder.getCurrentDebugLocation();
    111   if (Loc)
    112     CGF.Builder.SetCurrentDebugLocation(std::move(Loc));
    113 }
    114 
    115 ApplyDebugLocation::~ApplyDebugLocation() {
    116   // Query CGF so the location isn't overwritten when location updates are
    117   // temporarily disabled (for C++ default function arguments)
    118   if (CGF)
    119     CGF->Builder.SetCurrentDebugLocation(std::move(OriginalLocation));
    120 }
    121 
    122 void CGDebugInfo::setLocation(SourceLocation Loc) {
    123   // If the new location isn't valid return.
    124   if (Loc.isInvalid())
    125     return;
    126 
    127   CurLoc = CGM.getContext().getSourceManager().getExpansionLoc(Loc);
    128 
    129   // If we've changed files in the middle of a lexical scope go ahead
    130   // and create a new lexical scope with file node if it's different
    131   // from the one in the scope.
    132   if (LexicalBlockStack.empty())
    133     return;
    134 
    135   SourceManager &SM = CGM.getContext().getSourceManager();
    136   auto *Scope = cast<llvm::DIScope>(LexicalBlockStack.back());
    137   PresumedLoc PCLoc = SM.getPresumedLoc(CurLoc);
    138 
    139   if (PCLoc.isInvalid() || Scope->getFilename() == PCLoc.getFilename())
    140     return;
    141 
    142   if (auto *LBF = dyn_cast<llvm::DILexicalBlockFile>(Scope)) {
    143     LexicalBlockStack.pop_back();
    144     LexicalBlockStack.emplace_back(DBuilder.createLexicalBlockFile(
    145         LBF->getScope(), getOrCreateFile(CurLoc)));
    146   } else if (isa<llvm::DILexicalBlock>(Scope) ||
    147              isa<llvm::DISubprogram>(Scope)) {
    148     LexicalBlockStack.pop_back();
    149     LexicalBlockStack.emplace_back(
    150         DBuilder.createLexicalBlockFile(Scope, getOrCreateFile(CurLoc)));
    151   }
    152 }
    153 
    154 llvm::DIScope *CGDebugInfo::getDeclContextDescriptor(const Decl *D) {
    155   llvm::DIScope *Mod = getParentModuleOrNull(D);
    156   return getContextDescriptor(cast<Decl>(D->getDeclContext()),
    157                               Mod ? Mod : TheCU);
    158 }
    159 
    160 llvm::DIScope *CGDebugInfo::getContextDescriptor(const Decl *Context,
    161                                                  llvm::DIScope *Default) {
    162   if (!Context)
    163     return Default;
    164 
    165   auto I = RegionMap.find(Context);
    166   if (I != RegionMap.end()) {
    167     llvm::Metadata *V = I->second;
    168     return dyn_cast_or_null<llvm::DIScope>(V);
    169   }
    170 
    171   // Check namespace.
    172   if (const NamespaceDecl *NSDecl = dyn_cast<NamespaceDecl>(Context))
    173     return getOrCreateNameSpace(NSDecl);
    174 
    175   if (const RecordDecl *RDecl = dyn_cast<RecordDecl>(Context))
    176     if (!RDecl->isDependentType())
    177       return getOrCreateType(CGM.getContext().getTypeDeclType(RDecl),
    178                              getOrCreateMainFile());
    179   return Default;
    180 }
    181 
    182 StringRef CGDebugInfo::getFunctionName(const FunctionDecl *FD) {
    183   assert(FD && "Invalid FunctionDecl!");
    184   IdentifierInfo *FII = FD->getIdentifier();
    185   FunctionTemplateSpecializationInfo *Info =
    186       FD->getTemplateSpecializationInfo();
    187 
    188   // Emit the unqualified name in normal operation. LLVM and the debugger can
    189   // compute the fully qualified name from the scope chain. If we're only
    190   // emitting line table info, there won't be any scope chains, so emit the
    191   // fully qualified name here so that stack traces are more accurate.
    192   // FIXME: Do this when emitting DWARF as well as when emitting CodeView after
    193   // evaluating the size impact.
    194   bool UseQualifiedName = DebugKind == codegenoptions::DebugLineTablesOnly &&
    195                           CGM.getCodeGenOpts().EmitCodeView;
    196 
    197   if (!Info && FII && !UseQualifiedName)
    198     return FII->getName();
    199 
    200   SmallString<128> NS;
    201   llvm::raw_svector_ostream OS(NS);
    202   PrintingPolicy Policy(CGM.getLangOpts());
    203   Policy.MSVCFormatting = CGM.getCodeGenOpts().EmitCodeView;
    204   if (!UseQualifiedName)
    205     FD->printName(OS);
    206   else
    207     FD->printQualifiedName(OS, Policy);
    208 
    209   // Add any template specialization args.
    210   if (Info) {
    211     const TemplateArgumentList *TArgs = Info->TemplateArguments;
    212     TemplateSpecializationType::PrintTemplateArgumentList(OS, TArgs->asArray(),
    213                                                           Policy);
    214   }
    215 
    216   // Copy this name on the side and use its reference.
    217   return internString(OS.str());
    218 }
    219 
    220 StringRef CGDebugInfo::getObjCMethodName(const ObjCMethodDecl *OMD) {
    221   SmallString<256> MethodName;
    222   llvm::raw_svector_ostream OS(MethodName);
    223   OS << (OMD->isInstanceMethod() ? '-' : '+') << '[';
    224   const DeclContext *DC = OMD->getDeclContext();
    225   if (const ObjCImplementationDecl *OID =
    226           dyn_cast<const ObjCImplementationDecl>(DC)) {
    227     OS << OID->getName();
    228   } else if (const ObjCInterfaceDecl *OID =
    229                  dyn_cast<const ObjCInterfaceDecl>(DC)) {
    230     OS << OID->getName();
    231   } else if (const ObjCCategoryDecl *OC = dyn_cast<ObjCCategoryDecl>(DC)) {
    232     if (OC->IsClassExtension()) {
    233       OS << OC->getClassInterface()->getName();
    234     } else {
    235       OS << ((const NamedDecl *)OC)->getIdentifier()->getNameStart() << '('
    236          << OC->getIdentifier()->getNameStart() << ')';
    237     }
    238   } else if (const ObjCCategoryImplDecl *OCD =
    239                  dyn_cast<const ObjCCategoryImplDecl>(DC)) {
    240     OS << ((const NamedDecl *)OCD)->getIdentifier()->getNameStart() << '('
    241        << OCD->getIdentifier()->getNameStart() << ')';
    242   } else if (isa<ObjCProtocolDecl>(DC)) {
    243     // We can extract the type of the class from the self pointer.
    244     if (ImplicitParamDecl *SelfDecl = OMD->getSelfDecl()) {
    245       QualType ClassTy =
    246           cast<ObjCObjectPointerType>(SelfDecl->getType())->getPointeeType();
    247       ClassTy.print(OS, PrintingPolicy(LangOptions()));
    248     }
    249   }
    250   OS << ' ' << OMD->getSelector().getAsString() << ']';
    251 
    252   return internString(OS.str());
    253 }
    254 
    255 StringRef CGDebugInfo::getSelectorName(Selector S) {
    256   return internString(S.getAsString());
    257 }
    258 
    259 StringRef CGDebugInfo::getClassName(const RecordDecl *RD) {
    260   if (isa<ClassTemplateSpecializationDecl>(RD)) {
    261     SmallString<128> Name;
    262     llvm::raw_svector_ostream OS(Name);
    263     RD->getNameForDiagnostic(OS, CGM.getContext().getPrintingPolicy(),
    264                              /*Qualified*/ false);
    265 
    266     // Copy this name on the side and use its reference.
    267     return internString(Name);
    268   }
    269 
    270   // quick optimization to avoid having to intern strings that are already
    271   // stored reliably elsewhere
    272   if (const IdentifierInfo *II = RD->getIdentifier())
    273     return II->getName();
    274 
    275   // The CodeView printer in LLVM wants to see the names of unnamed types: it is
    276   // used to reconstruct the fully qualified type names.
    277   if (CGM.getCodeGenOpts().EmitCodeView) {
    278     if (const TypedefNameDecl *D = RD->getTypedefNameForAnonDecl()) {
    279       assert(RD->getDeclContext() == D->getDeclContext() &&
    280              "Typedef should not be in another decl context!");
    281       assert(D->getDeclName().getAsIdentifierInfo() &&
    282              "Typedef was not named!");
    283       return D->getDeclName().getAsIdentifierInfo()->getName();
    284     }
    285 
    286     if (CGM.getLangOpts().CPlusPlus) {
    287       StringRef Name;
    288 
    289       ASTContext &Context = CGM.getContext();
    290       if (const DeclaratorDecl *DD = Context.getDeclaratorForUnnamedTagDecl(RD))
    291         // Anonymous types without a name for linkage purposes have their
    292         // declarator mangled in if they have one.
    293         Name = DD->getName();
    294       else if (const TypedefNameDecl *TND =
    295                    Context.getTypedefNameForUnnamedTagDecl(RD))
    296         // Anonymous types without a name for linkage purposes have their
    297         // associate typedef mangled in if they have one.
    298         Name = TND->getName();
    299 
    300       if (!Name.empty()) {
    301         SmallString<256> UnnamedType("<unnamed-type-");
    302         UnnamedType += Name;
    303         UnnamedType += '>';
    304         return internString(UnnamedType);
    305       }
    306     }
    307   }
    308 
    309   return StringRef();
    310 }
    311 
    312 llvm::DIFile *CGDebugInfo::getOrCreateFile(SourceLocation Loc) {
    313   if (!Loc.isValid())
    314     // If Location is not valid then use main input file.
    315     return DBuilder.createFile(remapDIPath(TheCU->getFilename()),
    316                                remapDIPath(TheCU->getDirectory()));
    317 
    318   SourceManager &SM = CGM.getContext().getSourceManager();
    319   PresumedLoc PLoc = SM.getPresumedLoc(Loc);
    320 
    321   if (PLoc.isInvalid() || StringRef(PLoc.getFilename()).empty())
    322     // If the location is not valid then use main input file.
    323     return DBuilder.createFile(remapDIPath(TheCU->getFilename()),
    324                                remapDIPath(TheCU->getDirectory()));
    325 
    326   // Cache the results.
    327   const char *fname = PLoc.getFilename();
    328   auto it = DIFileCache.find(fname);
    329 
    330   if (it != DIFileCache.end()) {
    331     // Verify that the information still exists.
    332     if (llvm::Metadata *V = it->second)
    333       return cast<llvm::DIFile>(V);
    334   }
    335 
    336   llvm::DIFile *F = DBuilder.createFile(remapDIPath(PLoc.getFilename()),
    337                                         remapDIPath(getCurrentDirname()));
    338 
    339   DIFileCache[fname].reset(F);
    340   return F;
    341 }
    342 
    343 llvm::DIFile *CGDebugInfo::getOrCreateMainFile() {
    344   return DBuilder.createFile(remapDIPath(TheCU->getFilename()),
    345                              remapDIPath(TheCU->getDirectory()));
    346 }
    347 
    348 std::string CGDebugInfo::remapDIPath(StringRef Path) const {
    349   for (const auto &Entry : DebugPrefixMap)
    350     if (Path.startswith(Entry.first))
    351       return (Twine(Entry.second) + Path.substr(Entry.first.size())).str();
    352   return Path.str();
    353 }
    354 
    355 unsigned CGDebugInfo::getLineNumber(SourceLocation Loc) {
    356   if (Loc.isInvalid() && CurLoc.isInvalid())
    357     return 0;
    358   SourceManager &SM = CGM.getContext().getSourceManager();
    359   PresumedLoc PLoc = SM.getPresumedLoc(Loc.isValid() ? Loc : CurLoc);
    360   return PLoc.isValid() ? PLoc.getLine() : 0;
    361 }
    362 
    363 unsigned CGDebugInfo::getColumnNumber(SourceLocation Loc, bool Force) {
    364   // We may not want column information at all.
    365   if (!Force && !CGM.getCodeGenOpts().DebugColumnInfo)
    366     return 0;
    367 
    368   // If the location is invalid then use the current column.
    369   if (Loc.isInvalid() && CurLoc.isInvalid())
    370     return 0;
    371   SourceManager &SM = CGM.getContext().getSourceManager();
    372   PresumedLoc PLoc = SM.getPresumedLoc(Loc.isValid() ? Loc : CurLoc);
    373   return PLoc.isValid() ? PLoc.getColumn() : 0;
    374 }
    375 
    376 StringRef CGDebugInfo::getCurrentDirname() {
    377   if (!CGM.getCodeGenOpts().DebugCompilationDir.empty())
    378     return CGM.getCodeGenOpts().DebugCompilationDir;
    379 
    380   if (!CWDName.empty())
    381     return CWDName;
    382   SmallString<256> CWD;
    383   llvm::sys::fs::current_path(CWD);
    384   return CWDName = internString(CWD);
    385 }
    386 
    387 void CGDebugInfo::CreateCompileUnit() {
    388 
    389   // Should we be asking the SourceManager for the main file name, instead of
    390   // accepting it as an argument? This just causes the main file name to
    391   // mismatch with source locations and create extra lexical scopes or
    392   // mismatched debug info (a CU with a DW_AT_file of "-", because that's what
    393   // the driver passed, but functions/other things have DW_AT_file of "<stdin>"
    394   // because that's what the SourceManager says)
    395 
    396   // Get absolute path name.
    397   SourceManager &SM = CGM.getContext().getSourceManager();
    398   std::string MainFileName = CGM.getCodeGenOpts().MainFileName;
    399   if (MainFileName.empty())
    400     MainFileName = "<stdin>";
    401 
    402   // The main file name provided via the "-main-file-name" option contains just
    403   // the file name itself with no path information. This file name may have had
    404   // a relative path, so we look into the actual file entry for the main
    405   // file to determine the real absolute path for the file.
    406   std::string MainFileDir;
    407   if (const FileEntry *MainFile = SM.getFileEntryForID(SM.getMainFileID())) {
    408     MainFileDir = remapDIPath(MainFile->getDir()->getName());
    409     if (MainFileDir != ".") {
    410       llvm::SmallString<1024> MainFileDirSS(MainFileDir);
    411       llvm::sys::path::append(MainFileDirSS, MainFileName);
    412       MainFileName = MainFileDirSS.str();
    413     }
    414   }
    415 
    416   llvm::dwarf::SourceLanguage LangTag;
    417   const LangOptions &LO = CGM.getLangOpts();
    418   if (LO.CPlusPlus) {
    419     if (LO.ObjC1)
    420       LangTag = llvm::dwarf::DW_LANG_ObjC_plus_plus;
    421     else
    422       LangTag = llvm::dwarf::DW_LANG_C_plus_plus;
    423   } else if (LO.ObjC1) {
    424     LangTag = llvm::dwarf::DW_LANG_ObjC;
    425   } else if (LO.RenderScript) {
    426     LangTag = llvm::dwarf::DW_LANG_GOOGLE_RenderScript;
    427   } else if (LO.C99) {
    428     LangTag = llvm::dwarf::DW_LANG_C99;
    429   } else {
    430     LangTag = llvm::dwarf::DW_LANG_C89;
    431   }
    432 
    433   std::string Producer = getClangFullVersion();
    434 
    435   // Figure out which version of the ObjC runtime we have.
    436   unsigned RuntimeVers = 0;
    437   if (LO.ObjC1)
    438     RuntimeVers = LO.ObjCRuntime.isNonFragile() ? 2 : 1;
    439 
    440   llvm::DICompileUnit::DebugEmissionKind EmissionKind;
    441   switch (DebugKind) {
    442   case codegenoptions::NoDebugInfo:
    443   case codegenoptions::LocTrackingOnly:
    444     EmissionKind = llvm::DICompileUnit::NoDebug;
    445     break;
    446   case codegenoptions::DebugLineTablesOnly:
    447     EmissionKind = llvm::DICompileUnit::LineTablesOnly;
    448     break;
    449   case codegenoptions::LimitedDebugInfo:
    450   case codegenoptions::FullDebugInfo:
    451     EmissionKind = llvm::DICompileUnit::FullDebug;
    452     break;
    453   }
    454 
    455   // Create new compile unit.
    456   // FIXME - Eliminate TheCU.
    457   TheCU = DBuilder.createCompileUnit(
    458       LangTag, remapDIPath(MainFileName), remapDIPath(getCurrentDirname()),
    459       Producer, LO.Optimize, CGM.getCodeGenOpts().DwarfDebugFlags, RuntimeVers,
    460       CGM.getCodeGenOpts().SplitDwarfFile, EmissionKind, 0 /* DWOid */);
    461 }
    462 
    463 llvm::DIType *CGDebugInfo::CreateType(const BuiltinType *BT) {
    464   llvm::dwarf::TypeKind Encoding;
    465   StringRef BTName;
    466   switch (BT->getKind()) {
    467 #define BUILTIN_TYPE(Id, SingletonId)
    468 #define PLACEHOLDER_TYPE(Id, SingletonId) case BuiltinType::Id:
    469 #include "clang/AST/BuiltinTypes.def"
    470   case BuiltinType::Dependent:
    471     llvm_unreachable("Unexpected builtin type");
    472   case BuiltinType::NullPtr:
    473     return DBuilder.createNullPtrType();
    474   case BuiltinType::Void:
    475     return nullptr;
    476   case BuiltinType::ObjCClass:
    477     if (!ClassTy)
    478       ClassTy = DBuilder.createForwardDecl(llvm::dwarf::DW_TAG_structure_type,
    479                                            "objc_class", TheCU,
    480                                            getOrCreateMainFile(), 0);
    481     return ClassTy;
    482   case BuiltinType::ObjCId: {
    483     // typedef struct objc_class *Class;
    484     // typedef struct objc_object {
    485     //  Class isa;
    486     // } *id;
    487 
    488     if (ObjTy)
    489       return ObjTy;
    490 
    491     if (!ClassTy)
    492       ClassTy = DBuilder.createForwardDecl(llvm::dwarf::DW_TAG_structure_type,
    493                                            "objc_class", TheCU,
    494                                            getOrCreateMainFile(), 0);
    495 
    496     unsigned Size = CGM.getContext().getTypeSize(CGM.getContext().VoidPtrTy);
    497 
    498     auto *ISATy = DBuilder.createPointerType(ClassTy, Size);
    499 
    500     ObjTy =
    501         DBuilder.createStructType(TheCU, "objc_object", getOrCreateMainFile(),
    502                                   0, 0, 0, 0, nullptr, llvm::DINodeArray());
    503 
    504     DBuilder.replaceArrays(
    505         ObjTy,
    506         DBuilder.getOrCreateArray(&*DBuilder.createMemberType(
    507             ObjTy, "isa", getOrCreateMainFile(), 0, Size, 0, 0, 0, ISATy)));
    508     return ObjTy;
    509   }
    510   case BuiltinType::ObjCSel: {
    511     if (!SelTy)
    512       SelTy = DBuilder.createForwardDecl(llvm::dwarf::DW_TAG_structure_type,
    513                                          "objc_selector", TheCU,
    514                                          getOrCreateMainFile(), 0);
    515     return SelTy;
    516   }
    517 
    518 #define IMAGE_TYPE(ImgType, Id, SingletonId, Access, Suffix) \
    519   case BuiltinType::Id: \
    520     return getOrCreateStructPtrType("opencl_" #ImgType "_" #Suffix "_t", \
    521                                     SingletonId);
    522 #include "clang/Basic/OpenCLImageTypes.def"
    523   case BuiltinType::OCLSampler:
    524     return DBuilder.createBasicType(
    525         "opencl_sampler_t", CGM.getContext().getTypeSize(BT),
    526         CGM.getContext().getTypeAlign(BT), llvm::dwarf::DW_ATE_unsigned);
    527   case BuiltinType::OCLEvent:
    528     return getOrCreateStructPtrType("opencl_event_t", OCLEventDITy);
    529   case BuiltinType::OCLClkEvent:
    530     return getOrCreateStructPtrType("opencl_clk_event_t", OCLClkEventDITy);
    531   case BuiltinType::OCLQueue:
    532     return getOrCreateStructPtrType("opencl_queue_t", OCLQueueDITy);
    533   case BuiltinType::OCLNDRange:
    534     return getOrCreateStructPtrType("opencl_ndrange_t", OCLNDRangeDITy);
    535   case BuiltinType::OCLReserveID:
    536     return getOrCreateStructPtrType("opencl_reserve_id_t", OCLReserveIDDITy);
    537 
    538   case BuiltinType::UChar:
    539   case BuiltinType::Char_U:
    540     Encoding = llvm::dwarf::DW_ATE_unsigned_char;
    541     break;
    542   case BuiltinType::Char_S:
    543   case BuiltinType::SChar:
    544     Encoding = llvm::dwarf::DW_ATE_signed_char;
    545     break;
    546   case BuiltinType::Char16:
    547   case BuiltinType::Char32:
    548     Encoding = llvm::dwarf::DW_ATE_UTF;
    549     break;
    550   case BuiltinType::UShort:
    551   case BuiltinType::UInt:
    552   case BuiltinType::UInt128:
    553   case BuiltinType::ULong:
    554   case BuiltinType::WChar_U:
    555   case BuiltinType::ULongLong:
    556     Encoding = llvm::dwarf::DW_ATE_unsigned;
    557     break;
    558   case BuiltinType::Short:
    559   case BuiltinType::Int:
    560   case BuiltinType::Int128:
    561   case BuiltinType::Long:
    562   case BuiltinType::WChar_S:
    563   case BuiltinType::LongLong:
    564     Encoding = llvm::dwarf::DW_ATE_signed;
    565     break;
    566   case BuiltinType::Bool:
    567     Encoding = llvm::dwarf::DW_ATE_boolean;
    568     break;
    569   case BuiltinType::Half:
    570   case BuiltinType::Float:
    571   case BuiltinType::LongDouble:
    572   case BuiltinType::Float128:
    573   case BuiltinType::Double:
    574     // FIXME: For targets where long double and __float128 have the same size,
    575     // they are currently indistinguishable in the debugger without some
    576     // special treatment. However, there is currently no consensus on encoding
    577     // and this should be updated once a DWARF encoding exists for distinct
    578     // floating point types of the same size.
    579     Encoding = llvm::dwarf::DW_ATE_float;
    580     break;
    581   }
    582 
    583   switch (BT->getKind()) {
    584   case BuiltinType::Long:
    585     BTName = "long int";
    586     break;
    587   case BuiltinType::LongLong:
    588     BTName = "long long int";
    589     break;
    590   case BuiltinType::ULong:
    591     BTName = "long unsigned int";
    592     break;
    593   case BuiltinType::ULongLong:
    594     BTName = "long long unsigned int";
    595     break;
    596   default:
    597     BTName = BT->getName(CGM.getLangOpts());
    598     break;
    599   }
    600   // Bit size, align and offset of the type.
    601   uint64_t Size = CGM.getContext().getTypeSize(BT);
    602   uint64_t Align = CGM.getContext().getTypeAlign(BT);
    603   return DBuilder.createBasicType(BTName, Size, Align, Encoding);
    604 }
    605 
    606 llvm::DIType *CGDebugInfo::CreateType(const ComplexType *Ty) {
    607   // Bit size, align and offset of the type.
    608   llvm::dwarf::TypeKind Encoding = llvm::dwarf::DW_ATE_complex_float;
    609   if (Ty->isComplexIntegerType())
    610     Encoding = llvm::dwarf::DW_ATE_lo_user;
    611 
    612   uint64_t Size = CGM.getContext().getTypeSize(Ty);
    613   uint64_t Align = CGM.getContext().getTypeAlign(Ty);
    614   return DBuilder.createBasicType("complex", Size, Align, Encoding);
    615 }
    616 
    617 llvm::DIType *CGDebugInfo::CreateQualifiedType(QualType Ty,
    618                                                llvm::DIFile *Unit) {
    619   QualifierCollector Qc;
    620   const Type *T = Qc.strip(Ty);
    621 
    622   // Ignore these qualifiers for now.
    623   Qc.removeObjCGCAttr();
    624   Qc.removeAddressSpace();
    625   Qc.removeObjCLifetime();
    626 
    627   // We will create one Derived type for one qualifier and recurse to handle any
    628   // additional ones.
    629   llvm::dwarf::Tag Tag;
    630   if (Qc.hasConst()) {
    631     Tag = llvm::dwarf::DW_TAG_const_type;
    632     Qc.removeConst();
    633   } else if (Qc.hasVolatile()) {
    634     Tag = llvm::dwarf::DW_TAG_volatile_type;
    635     Qc.removeVolatile();
    636   } else if (Qc.hasRestrict()) {
    637     Tag = llvm::dwarf::DW_TAG_restrict_type;
    638     Qc.removeRestrict();
    639   } else {
    640     assert(Qc.empty() && "Unknown type qualifier for debug info");
    641     return getOrCreateType(QualType(T, 0), Unit);
    642   }
    643 
    644   auto *FromTy = getOrCreateType(Qc.apply(CGM.getContext(), T), Unit);
    645 
    646   // No need to fill in the Name, Line, Size, Alignment, Offset in case of
    647   // CVR derived types.
    648   return DBuilder.createQualifiedType(Tag, FromTy);
    649 }
    650 
    651 llvm::DIType *CGDebugInfo::CreateType(const ObjCObjectPointerType *Ty,
    652                                       llvm::DIFile *Unit) {
    653 
    654   // The frontend treats 'id' as a typedef to an ObjCObjectType,
    655   // whereas 'id<protocol>' is treated as an ObjCPointerType. For the
    656   // debug info, we want to emit 'id' in both cases.
    657   if (Ty->isObjCQualifiedIdType())
    658     return getOrCreateType(CGM.getContext().getObjCIdType(), Unit);
    659 
    660   return CreatePointerLikeType(llvm::dwarf::DW_TAG_pointer_type, Ty,
    661                                Ty->getPointeeType(), Unit);
    662 }
    663 
    664 llvm::DIType *CGDebugInfo::CreateType(const PointerType *Ty,
    665                                       llvm::DIFile *Unit) {
    666   return CreatePointerLikeType(llvm::dwarf::DW_TAG_pointer_type, Ty,
    667                                Ty->getPointeeType(), Unit);
    668 }
    669 
    670 /// \return whether a C++ mangling exists for the type defined by TD.
    671 static bool hasCXXMangling(const TagDecl *TD, llvm::DICompileUnit *TheCU) {
    672   switch (TheCU->getSourceLanguage()) {
    673   case llvm::dwarf::DW_LANG_C_plus_plus:
    674     return true;
    675   case llvm::dwarf::DW_LANG_ObjC_plus_plus:
    676     return isa<CXXRecordDecl>(TD) || isa<EnumDecl>(TD);
    677   default:
    678     return false;
    679   }
    680 }
    681 
    682 /// In C++ mode, types have linkage, so we can rely on the ODR and
    683 /// on their mangled names, if they're external.
    684 static SmallString<256> getUniqueTagTypeName(const TagType *Ty,
    685                                              CodeGenModule &CGM,
    686                                              llvm::DICompileUnit *TheCU) {
    687   SmallString<256> FullName;
    688   const TagDecl *TD = Ty->getDecl();
    689 
    690   if (!hasCXXMangling(TD, TheCU) || !TD->isExternallyVisible())
    691     return FullName;
    692 
    693   // TODO: This is using the RTTI name. Is there a better way to get
    694   // a unique string for a type?
    695   llvm::raw_svector_ostream Out(FullName);
    696   CGM.getCXXABI().getMangleContext().mangleCXXRTTIName(QualType(Ty, 0), Out);
    697   return FullName;
    698 }
    699 
    700 /// \return the approproate DWARF tag for a composite type.
    701 static llvm::dwarf::Tag getTagForRecord(const RecordDecl *RD) {
    702    llvm::dwarf::Tag Tag;
    703   if (RD->isStruct() || RD->isInterface())
    704     Tag = llvm::dwarf::DW_TAG_structure_type;
    705   else if (RD->isUnion())
    706     Tag = llvm::dwarf::DW_TAG_union_type;
    707   else {
    708     // FIXME: This could be a struct type giving a default visibility different
    709     // than C++ class type, but needs llvm metadata changes first.
    710     assert(RD->isClass());
    711     Tag = llvm::dwarf::DW_TAG_class_type;
    712   }
    713   return Tag;
    714 }
    715 
    716 llvm::DICompositeType *
    717 CGDebugInfo::getOrCreateRecordFwdDecl(const RecordType *Ty,
    718                                       llvm::DIScope *Ctx) {
    719   const RecordDecl *RD = Ty->getDecl();
    720   if (llvm::DIType *T = getTypeOrNull(CGM.getContext().getRecordType(RD)))
    721     return cast<llvm::DICompositeType>(T);
    722   llvm::DIFile *DefUnit = getOrCreateFile(RD->getLocation());
    723   unsigned Line = getLineNumber(RD->getLocation());
    724   StringRef RDName = getClassName(RD);
    725 
    726   uint64_t Size = 0;
    727   uint64_t Align = 0;
    728 
    729   const RecordDecl *D = RD->getDefinition();
    730   if (D && D->isCompleteDefinition()) {
    731     Size = CGM.getContext().getTypeSize(Ty);
    732     Align = CGM.getContext().getTypeAlign(Ty);
    733   }
    734 
    735   // Create the type.
    736   SmallString<256> FullName = getUniqueTagTypeName(Ty, CGM, TheCU);
    737   llvm::DICompositeType *RetTy = DBuilder.createReplaceableCompositeType(
    738       getTagForRecord(RD), RDName, Ctx, DefUnit, Line, 0, Size, Align,
    739       llvm::DINode::FlagFwdDecl, FullName);
    740   ReplaceMap.emplace_back(
    741       std::piecewise_construct, std::make_tuple(Ty),
    742       std::make_tuple(static_cast<llvm::Metadata *>(RetTy)));
    743   return RetTy;
    744 }
    745 
    746 llvm::DIType *CGDebugInfo::CreatePointerLikeType(llvm::dwarf::Tag Tag,
    747                                                  const Type *Ty,
    748                                                  QualType PointeeTy,
    749                                                  llvm::DIFile *Unit) {
    750   // Bit size, align and offset of the type.
    751   // Size is always the size of a pointer. We can't use getTypeSize here
    752   // because that does not return the correct value for references.
    753   unsigned AS = CGM.getContext().getTargetAddressSpace(PointeeTy);
    754   uint64_t Size = CGM.getTarget().getPointerWidth(AS);
    755   uint64_t Align = CGM.getContext().getTypeAlign(Ty);
    756 
    757   if (Tag == llvm::dwarf::DW_TAG_reference_type ||
    758       Tag == llvm::dwarf::DW_TAG_rvalue_reference_type)
    759     return DBuilder.createReferenceType(Tag, getOrCreateType(PointeeTy, Unit),
    760                                         Size, Align);
    761   else
    762     return DBuilder.createPointerType(getOrCreateType(PointeeTy, Unit), Size,
    763                                       Align);
    764 }
    765 
    766 llvm::DIType *CGDebugInfo::getOrCreateStructPtrType(StringRef Name,
    767                                                     llvm::DIType *&Cache) {
    768   if (Cache)
    769     return Cache;
    770   Cache = DBuilder.createForwardDecl(llvm::dwarf::DW_TAG_structure_type, Name,
    771                                      TheCU, getOrCreateMainFile(), 0);
    772   unsigned Size = CGM.getContext().getTypeSize(CGM.getContext().VoidPtrTy);
    773   Cache = DBuilder.createPointerType(Cache, Size);
    774   return Cache;
    775 }
    776 
    777 llvm::DIType *CGDebugInfo::CreateType(const BlockPointerType *Ty,
    778                                       llvm::DIFile *Unit) {
    779   SmallVector<llvm::Metadata *, 8> EltTys;
    780   QualType FType;
    781   uint64_t FieldSize, FieldOffset;
    782   unsigned FieldAlign;
    783   llvm::DINodeArray Elements;
    784 
    785   FieldOffset = 0;
    786   FType = CGM.getContext().UnsignedLongTy;
    787   EltTys.push_back(CreateMemberType(Unit, FType, "reserved", &FieldOffset));
    788   EltTys.push_back(CreateMemberType(Unit, FType, "Size", &FieldOffset));
    789 
    790   Elements = DBuilder.getOrCreateArray(EltTys);
    791   EltTys.clear();
    792 
    793   unsigned Flags = llvm::DINode::FlagAppleBlock;
    794   unsigned LineNo = 0;
    795 
    796   auto *EltTy =
    797       DBuilder.createStructType(Unit, "__block_descriptor", nullptr, LineNo,
    798                                 FieldOffset, 0, Flags, nullptr, Elements);
    799 
    800   // Bit size, align and offset of the type.
    801   uint64_t Size = CGM.getContext().getTypeSize(Ty);
    802 
    803   auto *DescTy = DBuilder.createPointerType(EltTy, Size);
    804 
    805   FieldOffset = 0;
    806   FType = CGM.getContext().getPointerType(CGM.getContext().VoidTy);
    807   EltTys.push_back(CreateMemberType(Unit, FType, "__isa", &FieldOffset));
    808   FType = CGM.getContext().IntTy;
    809   EltTys.push_back(CreateMemberType(Unit, FType, "__flags", &FieldOffset));
    810   EltTys.push_back(CreateMemberType(Unit, FType, "__reserved", &FieldOffset));
    811   FType = CGM.getContext().getPointerType(Ty->getPointeeType());
    812   EltTys.push_back(CreateMemberType(Unit, FType, "__FuncPtr", &FieldOffset));
    813 
    814   FType = CGM.getContext().getPointerType(CGM.getContext().VoidTy);
    815   FieldSize = CGM.getContext().getTypeSize(Ty);
    816   FieldAlign = CGM.getContext().getTypeAlign(Ty);
    817   EltTys.push_back(DBuilder.createMemberType(Unit, "__descriptor", nullptr, LineNo,
    818                                              FieldSize, FieldAlign, FieldOffset,
    819                                              0, DescTy));
    820 
    821   FieldOffset += FieldSize;
    822   Elements = DBuilder.getOrCreateArray(EltTys);
    823 
    824   // The __block_literal_generic structs are marked with a special
    825   // DW_AT_APPLE_BLOCK attribute and are an implementation detail only
    826   // the debugger needs to know about. To allow type uniquing, emit
    827   // them without a name or a location.
    828   EltTy =
    829       DBuilder.createStructType(Unit, "", nullptr, LineNo,
    830                                 FieldOffset, 0, Flags, nullptr, Elements);
    831 
    832   return DBuilder.createPointerType(EltTy, Size);
    833 }
    834 
    835 llvm::DIType *CGDebugInfo::CreateType(const TemplateSpecializationType *Ty,
    836                                       llvm::DIFile *Unit) {
    837   assert(Ty->isTypeAlias());
    838   llvm::DIType *Src = getOrCreateType(Ty->getAliasedType(), Unit);
    839 
    840   SmallString<128> NS;
    841   llvm::raw_svector_ostream OS(NS);
    842   Ty->getTemplateName().print(OS, CGM.getContext().getPrintingPolicy(),
    843                               /*qualified*/ false);
    844 
    845   TemplateSpecializationType::PrintTemplateArgumentList(
    846       OS, Ty->template_arguments(),
    847       CGM.getContext().getPrintingPolicy());
    848 
    849   TypeAliasDecl *AliasDecl = cast<TypeAliasTemplateDecl>(
    850       Ty->getTemplateName().getAsTemplateDecl())->getTemplatedDecl();
    851 
    852   SourceLocation Loc = AliasDecl->getLocation();
    853   return DBuilder.createTypedef(Src, OS.str(), getOrCreateFile(Loc),
    854                                 getLineNumber(Loc),
    855                                 getDeclContextDescriptor(AliasDecl));
    856 }
    857 
    858 llvm::DIType *CGDebugInfo::CreateType(const TypedefType *Ty,
    859                                       llvm::DIFile *Unit) {
    860   // We don't set size information, but do specify where the typedef was
    861   // declared.
    862   SourceLocation Loc = Ty->getDecl()->getLocation();
    863 
    864   // Typedefs are derived from some other type.
    865   return DBuilder.createTypedef(
    866       getOrCreateType(Ty->getDecl()->getUnderlyingType(), Unit),
    867       Ty->getDecl()->getName(), getOrCreateFile(Loc), getLineNumber(Loc),
    868       getDeclContextDescriptor(Ty->getDecl()));
    869 }
    870 
    871 static unsigned getDwarfCC(CallingConv CC) {
    872   switch (CC) {
    873   case CC_C:
    874     // Avoid emitting DW_AT_calling_convention if the C convention was used.
    875     return 0;
    876 
    877   case CC_X86StdCall:
    878     return llvm::dwarf::DW_CC_BORLAND_stdcall;
    879   case CC_X86FastCall:
    880     return llvm::dwarf::DW_CC_BORLAND_msfastcall;
    881   case CC_X86ThisCall:
    882     return llvm::dwarf::DW_CC_BORLAND_thiscall;
    883   case CC_X86VectorCall:
    884     return llvm::dwarf::DW_CC_LLVM_vectorcall;
    885   case CC_X86Pascal:
    886     return llvm::dwarf::DW_CC_BORLAND_pascal;
    887 
    888   // FIXME: Create new DW_CC_ codes for these calling conventions.
    889   case CC_X86_64Win64:
    890   case CC_X86_64SysV:
    891   case CC_AAPCS:
    892   case CC_AAPCS_VFP:
    893   case CC_IntelOclBicc:
    894   case CC_SpirFunction:
    895   case CC_OpenCLKernel:
    896   case CC_Swift:
    897   case CC_PreserveMost:
    898   case CC_PreserveAll:
    899     return 0;
    900   }
    901   return 0;
    902 }
    903 
    904 llvm::DIType *CGDebugInfo::CreateType(const FunctionType *Ty,
    905                                       llvm::DIFile *Unit) {
    906   SmallVector<llvm::Metadata *, 16> EltTys;
    907 
    908   // Add the result type at least.
    909   EltTys.push_back(getOrCreateType(Ty->getReturnType(), Unit));
    910 
    911   // Set up remainder of arguments if there is a prototype.
    912   // otherwise emit it as a variadic function.
    913   if (isa<FunctionNoProtoType>(Ty))
    914     EltTys.push_back(DBuilder.createUnspecifiedParameter());
    915   else if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(Ty)) {
    916     for (unsigned i = 0, e = FPT->getNumParams(); i != e; ++i)
    917       EltTys.push_back(getOrCreateType(FPT->getParamType(i), Unit));
    918     if (FPT->isVariadic())
    919       EltTys.push_back(DBuilder.createUnspecifiedParameter());
    920   }
    921 
    922   llvm::DITypeRefArray EltTypeArray = DBuilder.getOrCreateTypeArray(EltTys);
    923   return DBuilder.createSubroutineType(EltTypeArray, 0,
    924                                        getDwarfCC(Ty->getCallConv()));
    925 }
    926 
    927 /// Convert an AccessSpecifier into the corresponding DINode flag.
    928 /// As an optimization, return 0 if the access specifier equals the
    929 /// default for the containing type.
    930 static unsigned getAccessFlag(AccessSpecifier Access, const RecordDecl *RD) {
    931   AccessSpecifier Default = clang::AS_none;
    932   if (RD && RD->isClass())
    933     Default = clang::AS_private;
    934   else if (RD && (RD->isStruct() || RD->isUnion()))
    935     Default = clang::AS_public;
    936 
    937   if (Access == Default)
    938     return 0;
    939 
    940   switch (Access) {
    941   case clang::AS_private:
    942     return llvm::DINode::FlagPrivate;
    943   case clang::AS_protected:
    944     return llvm::DINode::FlagProtected;
    945   case clang::AS_public:
    946     return llvm::DINode::FlagPublic;
    947   case clang::AS_none:
    948     return 0;
    949   }
    950   llvm_unreachable("unexpected access enumerator");
    951 }
    952 
    953 llvm::DIType *CGDebugInfo::createBitFieldType(const FieldDecl *BitFieldDecl,
    954                                               llvm::DIScope *RecordTy,
    955                                               const RecordDecl *RD) {
    956   StringRef Name = BitFieldDecl->getName();
    957   QualType Ty = BitFieldDecl->getType();
    958   SourceLocation Loc = BitFieldDecl->getLocation();
    959   llvm::DIFile *VUnit = getOrCreateFile(Loc);
    960   llvm::DIType *DebugType = getOrCreateType(Ty, VUnit);
    961 
    962   // Get the location for the field.
    963   llvm::DIFile *File = getOrCreateFile(Loc);
    964   unsigned Line = getLineNumber(Loc);
    965 
    966   const CGBitFieldInfo &BitFieldInfo =
    967       CGM.getTypes().getCGRecordLayout(RD).getBitFieldInfo(BitFieldDecl);
    968   uint64_t SizeInBits = BitFieldInfo.Size;
    969   assert(SizeInBits > 0 && "found named 0-width bitfield");
    970   unsigned AlignInBits = CGM.getContext().getTypeAlign(Ty);
    971   uint64_t StorageOffsetInBits =
    972       CGM.getContext().toBits(BitFieldInfo.StorageOffset);
    973   uint64_t OffsetInBits = StorageOffsetInBits + BitFieldInfo.Offset;
    974   unsigned Flags = getAccessFlag(BitFieldDecl->getAccess(), RD);
    975   return DBuilder.createBitFieldMemberType(
    976       RecordTy, Name, File, Line, SizeInBits, AlignInBits, OffsetInBits,
    977       StorageOffsetInBits, Flags, DebugType);
    978 }
    979 
    980 llvm::DIType *
    981 CGDebugInfo::createFieldType(StringRef name, QualType type, SourceLocation loc,
    982                              AccessSpecifier AS, uint64_t offsetInBits,
    983                              llvm::DIFile *tunit, llvm::DIScope *scope,
    984                              const RecordDecl *RD) {
    985   llvm::DIType *debugType = getOrCreateType(type, tunit);
    986 
    987   // Get the location for the field.
    988   llvm::DIFile *file = getOrCreateFile(loc);
    989   unsigned line = getLineNumber(loc);
    990 
    991   uint64_t SizeInBits = 0;
    992   unsigned AlignInBits = 0;
    993   if (!type->isIncompleteArrayType()) {
    994     TypeInfo TI = CGM.getContext().getTypeInfo(type);
    995     SizeInBits = TI.Width;
    996     AlignInBits = TI.Align;
    997   }
    998 
    999   unsigned flags = getAccessFlag(AS, RD);
   1000   return DBuilder.createMemberType(scope, name, file, line, SizeInBits,
   1001                                    AlignInBits, offsetInBits, flags, debugType);
   1002 }
   1003 
   1004 void CGDebugInfo::CollectRecordLambdaFields(
   1005     const CXXRecordDecl *CXXDecl, SmallVectorImpl<llvm::Metadata *> &elements,
   1006     llvm::DIType *RecordTy) {
   1007   // For C++11 Lambdas a Field will be the same as a Capture, but the Capture
   1008   // has the name and the location of the variable so we should iterate over
   1009   // both concurrently.
   1010   const ASTRecordLayout &layout = CGM.getContext().getASTRecordLayout(CXXDecl);
   1011   RecordDecl::field_iterator Field = CXXDecl->field_begin();
   1012   unsigned fieldno = 0;
   1013   for (CXXRecordDecl::capture_const_iterator I = CXXDecl->captures_begin(),
   1014                                              E = CXXDecl->captures_end();
   1015        I != E; ++I, ++Field, ++fieldno) {
   1016     const LambdaCapture &C = *I;
   1017     if (C.capturesVariable()) {
   1018       SourceLocation Loc = C.getLocation();
   1019       assert(!Field->isBitField() && "lambdas don't have bitfield members!");
   1020       VarDecl *V = C.getCapturedVar();
   1021       StringRef VName = V->getName();
   1022       llvm::DIFile *VUnit = getOrCreateFile(Loc);
   1023       llvm::DIType *FieldType = createFieldType(
   1024           VName, Field->getType(), Loc, Field->getAccess(),
   1025           layout.getFieldOffset(fieldno), VUnit, RecordTy, CXXDecl);
   1026       elements.push_back(FieldType);
   1027     } else if (C.capturesThis()) {
   1028       // TODO: Need to handle 'this' in some way by probably renaming the
   1029       // this of the lambda class and having a field member of 'this' or
   1030       // by using AT_object_pointer for the function and having that be
   1031       // used as 'this' for semantic references.
   1032       FieldDecl *f = *Field;
   1033       llvm::DIFile *VUnit = getOrCreateFile(f->getLocation());
   1034       QualType type = f->getType();
   1035       llvm::DIType *fieldType = createFieldType(
   1036           "this", type, f->getLocation(), f->getAccess(),
   1037           layout.getFieldOffset(fieldno), VUnit, RecordTy, CXXDecl);
   1038 
   1039       elements.push_back(fieldType);
   1040     }
   1041   }
   1042 }
   1043 
   1044 llvm::DIDerivedType *
   1045 CGDebugInfo::CreateRecordStaticField(const VarDecl *Var, llvm::DIType *RecordTy,
   1046                                      const RecordDecl *RD) {
   1047   // Create the descriptor for the static variable, with or without
   1048   // constant initializers.
   1049   Var = Var->getCanonicalDecl();
   1050   llvm::DIFile *VUnit = getOrCreateFile(Var->getLocation());
   1051   llvm::DIType *VTy = getOrCreateType(Var->getType(), VUnit);
   1052 
   1053   unsigned LineNumber = getLineNumber(Var->getLocation());
   1054   StringRef VName = Var->getName();
   1055   llvm::Constant *C = nullptr;
   1056   if (Var->getInit()) {
   1057     const APValue *Value = Var->evaluateValue();
   1058     if (Value) {
   1059       if (Value->isInt())
   1060         C = llvm::ConstantInt::get(CGM.getLLVMContext(), Value->getInt());
   1061       if (Value->isFloat())
   1062         C = llvm::ConstantFP::get(CGM.getLLVMContext(), Value->getFloat());
   1063     }
   1064   }
   1065 
   1066   unsigned Flags = getAccessFlag(Var->getAccess(), RD);
   1067   llvm::DIDerivedType *GV = DBuilder.createStaticMemberType(
   1068       RecordTy, VName, VUnit, LineNumber, VTy, Flags, C);
   1069   StaticDataMemberCache[Var->getCanonicalDecl()].reset(GV);
   1070   return GV;
   1071 }
   1072 
   1073 void CGDebugInfo::CollectRecordNormalField(
   1074     const FieldDecl *field, uint64_t OffsetInBits, llvm::DIFile *tunit,
   1075     SmallVectorImpl<llvm::Metadata *> &elements, llvm::DIType *RecordTy,
   1076     const RecordDecl *RD) {
   1077   StringRef name = field->getName();
   1078   QualType type = field->getType();
   1079 
   1080   // Ignore unnamed fields unless they're anonymous structs/unions.
   1081   if (name.empty() && !type->isRecordType())
   1082     return;
   1083 
   1084   llvm::DIType *FieldType;
   1085   if (field->isBitField()) {
   1086     FieldType = createBitFieldType(field, RecordTy, RD);
   1087   } else {
   1088     FieldType =
   1089         createFieldType(name, type, field->getLocation(), field->getAccess(),
   1090                         OffsetInBits, tunit, RecordTy, RD);
   1091   }
   1092 
   1093   elements.push_back(FieldType);
   1094 }
   1095 
   1096 void CGDebugInfo::CollectRecordFields(
   1097     const RecordDecl *record, llvm::DIFile *tunit,
   1098     SmallVectorImpl<llvm::Metadata *> &elements,
   1099     llvm::DICompositeType *RecordTy) {
   1100   const CXXRecordDecl *CXXDecl = dyn_cast<CXXRecordDecl>(record);
   1101 
   1102   if (CXXDecl && CXXDecl->isLambda())
   1103     CollectRecordLambdaFields(CXXDecl, elements, RecordTy);
   1104   else {
   1105     const ASTRecordLayout &layout = CGM.getContext().getASTRecordLayout(record);
   1106 
   1107     // Field number for non-static fields.
   1108     unsigned fieldNo = 0;
   1109 
   1110     // Static and non-static members should appear in the same order as
   1111     // the corresponding declarations in the source program.
   1112     for (const auto *I : record->decls())
   1113       if (const auto *V = dyn_cast<VarDecl>(I)) {
   1114         if (V->hasAttr<NoDebugAttr>())
   1115           continue;
   1116         // Reuse the existing static member declaration if one exists
   1117         auto MI = StaticDataMemberCache.find(V->getCanonicalDecl());
   1118         if (MI != StaticDataMemberCache.end()) {
   1119           assert(MI->second &&
   1120                  "Static data member declaration should still exist");
   1121           elements.push_back(MI->second);
   1122         } else {
   1123           auto Field = CreateRecordStaticField(V, RecordTy, record);
   1124           elements.push_back(Field);
   1125         }
   1126       } else if (const auto *field = dyn_cast<FieldDecl>(I)) {
   1127         CollectRecordNormalField(field, layout.getFieldOffset(fieldNo), tunit,
   1128                                  elements, RecordTy, record);
   1129 
   1130         // Bump field number for next field.
   1131         ++fieldNo;
   1132       }
   1133   }
   1134 }
   1135 
   1136 llvm::DISubroutineType *
   1137 CGDebugInfo::getOrCreateMethodType(const CXXMethodDecl *Method,
   1138                                    llvm::DIFile *Unit) {
   1139   const FunctionProtoType *Func = Method->getType()->getAs<FunctionProtoType>();
   1140   if (Method->isStatic())
   1141     return cast_or_null<llvm::DISubroutineType>(
   1142         getOrCreateType(QualType(Func, 0), Unit));
   1143   return getOrCreateInstanceMethodType(Method->getThisType(CGM.getContext()),
   1144                                        Func, Unit);
   1145 }
   1146 
   1147 llvm::DISubroutineType *CGDebugInfo::getOrCreateInstanceMethodType(
   1148     QualType ThisPtr, const FunctionProtoType *Func, llvm::DIFile *Unit) {
   1149   // Add "this" pointer.
   1150   llvm::DITypeRefArray Args(
   1151       cast<llvm::DISubroutineType>(getOrCreateType(QualType(Func, 0), Unit))
   1152           ->getTypeArray());
   1153   assert(Args.size() && "Invalid number of arguments!");
   1154 
   1155   SmallVector<llvm::Metadata *, 16> Elts;
   1156 
   1157   // First element is always return type. For 'void' functions it is NULL.
   1158   Elts.push_back(Args[0]);
   1159 
   1160   // "this" pointer is always first argument.
   1161   const CXXRecordDecl *RD = ThisPtr->getPointeeCXXRecordDecl();
   1162   if (isa<ClassTemplateSpecializationDecl>(RD)) {
   1163     // Create pointer type directly in this case.
   1164     const PointerType *ThisPtrTy = cast<PointerType>(ThisPtr);
   1165     QualType PointeeTy = ThisPtrTy->getPointeeType();
   1166     unsigned AS = CGM.getContext().getTargetAddressSpace(PointeeTy);
   1167     uint64_t Size = CGM.getTarget().getPointerWidth(AS);
   1168     uint64_t Align = CGM.getContext().getTypeAlign(ThisPtrTy);
   1169     llvm::DIType *PointeeType = getOrCreateType(PointeeTy, Unit);
   1170     llvm::DIType *ThisPtrType =
   1171         DBuilder.createPointerType(PointeeType, Size, Align);
   1172     TypeCache[ThisPtr.getAsOpaquePtr()].reset(ThisPtrType);
   1173     // TODO: This and the artificial type below are misleading, the
   1174     // types aren't artificial the argument is, but the current
   1175     // metadata doesn't represent that.
   1176     ThisPtrType = DBuilder.createObjectPointerType(ThisPtrType);
   1177     Elts.push_back(ThisPtrType);
   1178   } else {
   1179     llvm::DIType *ThisPtrType = getOrCreateType(ThisPtr, Unit);
   1180     TypeCache[ThisPtr.getAsOpaquePtr()].reset(ThisPtrType);
   1181     ThisPtrType = DBuilder.createObjectPointerType(ThisPtrType);
   1182     Elts.push_back(ThisPtrType);
   1183   }
   1184 
   1185   // Copy rest of the arguments.
   1186   for (unsigned i = 1, e = Args.size(); i != e; ++i)
   1187     Elts.push_back(Args[i]);
   1188 
   1189   llvm::DITypeRefArray EltTypeArray = DBuilder.getOrCreateTypeArray(Elts);
   1190 
   1191   unsigned Flags = 0;
   1192   if (Func->getExtProtoInfo().RefQualifier == RQ_LValue)
   1193     Flags |= llvm::DINode::FlagLValueReference;
   1194   if (Func->getExtProtoInfo().RefQualifier == RQ_RValue)
   1195     Flags |= llvm::DINode::FlagRValueReference;
   1196 
   1197   return DBuilder.createSubroutineType(EltTypeArray, Flags,
   1198                                        getDwarfCC(Func->getCallConv()));
   1199 }
   1200 
   1201 /// isFunctionLocalClass - Return true if CXXRecordDecl is defined
   1202 /// inside a function.
   1203 static bool isFunctionLocalClass(const CXXRecordDecl *RD) {
   1204   if (const CXXRecordDecl *NRD = dyn_cast<CXXRecordDecl>(RD->getDeclContext()))
   1205     return isFunctionLocalClass(NRD);
   1206   if (isa<FunctionDecl>(RD->getDeclContext()))
   1207     return true;
   1208   return false;
   1209 }
   1210 
   1211 llvm::DISubprogram *CGDebugInfo::CreateCXXMemberFunction(
   1212     const CXXMethodDecl *Method, llvm::DIFile *Unit, llvm::DIType *RecordTy) {
   1213   bool IsCtorOrDtor =
   1214       isa<CXXConstructorDecl>(Method) || isa<CXXDestructorDecl>(Method);
   1215 
   1216   StringRef MethodName = getFunctionName(Method);
   1217   llvm::DISubroutineType *MethodTy = getOrCreateMethodType(Method, Unit);
   1218 
   1219   // Since a single ctor/dtor corresponds to multiple functions, it doesn't
   1220   // make sense to give a single ctor/dtor a linkage name.
   1221   StringRef MethodLinkageName;
   1222   // FIXME: 'isFunctionLocalClass' seems like an arbitrary/unintentional
   1223   // property to use here. It may've been intended to model "is non-external
   1224   // type" but misses cases of non-function-local but non-external classes such
   1225   // as those in anonymous namespaces as well as the reverse - external types
   1226   // that are function local, such as those in (non-local) inline functions.
   1227   if (!IsCtorOrDtor && !isFunctionLocalClass(Method->getParent()))
   1228     MethodLinkageName = CGM.getMangledName(Method);
   1229 
   1230   // Get the location for the method.
   1231   llvm::DIFile *MethodDefUnit = nullptr;
   1232   unsigned MethodLine = 0;
   1233   if (!Method->isImplicit()) {
   1234     MethodDefUnit = getOrCreateFile(Method->getLocation());
   1235     MethodLine = getLineNumber(Method->getLocation());
   1236   }
   1237 
   1238   // Collect virtual method info.
   1239   llvm::DIType *ContainingType = nullptr;
   1240   unsigned Virtuality = 0;
   1241   unsigned VIndex = 0;
   1242   unsigned Flags = 0;
   1243   int ThisAdjustment = 0;
   1244 
   1245   if (Method->isVirtual()) {
   1246     if (Method->isPure())
   1247       Virtuality = llvm::dwarf::DW_VIRTUALITY_pure_virtual;
   1248     else
   1249       Virtuality = llvm::dwarf::DW_VIRTUALITY_virtual;
   1250 
   1251     if (CGM.getTarget().getCXXABI().isItaniumFamily()) {
   1252       // It doesn't make sense to give a virtual destructor a vtable index,
   1253       // since a single destructor has two entries in the vtable.
   1254       if (!isa<CXXDestructorDecl>(Method))
   1255         VIndex = CGM.getItaniumVTableContext().getMethodVTableIndex(Method);
   1256     } else {
   1257       // Emit MS ABI vftable information.  There is only one entry for the
   1258       // deleting dtor.
   1259       const auto *DD = dyn_cast<CXXDestructorDecl>(Method);
   1260       GlobalDecl GD = DD ? GlobalDecl(DD, Dtor_Deleting) : GlobalDecl(Method);
   1261       MicrosoftVTableContext::MethodVFTableLocation ML =
   1262           CGM.getMicrosoftVTableContext().getMethodVFTableLocation(GD);
   1263       VIndex = ML.Index;
   1264 
   1265       // CodeView only records the vftable offset in the class that introduces
   1266       // the virtual method. This is possible because, unlike Itanium, the MS
   1267       // C++ ABI does not include all virtual methods from non-primary bases in
   1268       // the vtable for the most derived class. For example, if C inherits from
   1269       // A and B, C's primary vftable will not include B's virtual methods.
   1270       if (Method->begin_overridden_methods() == Method->end_overridden_methods())
   1271         Flags |= llvm::DINode::FlagIntroducedVirtual;
   1272 
   1273       // The 'this' adjustment accounts for both the virtual and non-virtual
   1274       // portions of the adjustment. Presumably the debugger only uses it when
   1275       // it knows the dynamic type of an object.
   1276       ThisAdjustment = CGM.getCXXABI()
   1277                            .getVirtualFunctionPrologueThisAdjustment(GD)
   1278                            .getQuantity();
   1279     }
   1280     ContainingType = RecordTy;
   1281   }
   1282 
   1283   if (Method->isImplicit())
   1284     Flags |= llvm::DINode::FlagArtificial;
   1285   Flags |= getAccessFlag(Method->getAccess(), Method->getParent());
   1286   if (const CXXConstructorDecl *CXXC = dyn_cast<CXXConstructorDecl>(Method)) {
   1287     if (CXXC->isExplicit())
   1288       Flags |= llvm::DINode::FlagExplicit;
   1289   } else if (const CXXConversionDecl *CXXC =
   1290                  dyn_cast<CXXConversionDecl>(Method)) {
   1291     if (CXXC->isExplicit())
   1292       Flags |= llvm::DINode::FlagExplicit;
   1293   }
   1294   if (Method->hasPrototype())
   1295     Flags |= llvm::DINode::FlagPrototyped;
   1296   if (Method->getRefQualifier() == RQ_LValue)
   1297     Flags |= llvm::DINode::FlagLValueReference;
   1298   if (Method->getRefQualifier() == RQ_RValue)
   1299     Flags |= llvm::DINode::FlagRValueReference;
   1300 
   1301   llvm::DINodeArray TParamsArray = CollectFunctionTemplateParams(Method, Unit);
   1302   llvm::DISubprogram *SP = DBuilder.createMethod(
   1303       RecordTy, MethodName, MethodLinkageName, MethodDefUnit, MethodLine,
   1304       MethodTy, /*isLocalToUnit=*/false, /*isDefinition=*/false, Virtuality,
   1305       VIndex, ThisAdjustment, ContainingType, Flags, CGM.getLangOpts().Optimize,
   1306       TParamsArray.get());
   1307 
   1308   SPCache[Method->getCanonicalDecl()].reset(SP);
   1309 
   1310   return SP;
   1311 }
   1312 
   1313 void CGDebugInfo::CollectCXXMemberFunctions(
   1314     const CXXRecordDecl *RD, llvm::DIFile *Unit,
   1315     SmallVectorImpl<llvm::Metadata *> &EltTys, llvm::DIType *RecordTy) {
   1316 
   1317   // Since we want more than just the individual member decls if we
   1318   // have templated functions iterate over every declaration to gather
   1319   // the functions.
   1320   for (const auto *I : RD->decls()) {
   1321     const auto *Method = dyn_cast<CXXMethodDecl>(I);
   1322     // If the member is implicit, don't add it to the member list. This avoids
   1323     // the member being added to type units by LLVM, while still allowing it
   1324     // to be emitted into the type declaration/reference inside the compile
   1325     // unit.
   1326     // Ditto 'nodebug' methods, for consistency with CodeGenFunction.cpp.
   1327     // FIXME: Handle Using(Shadow?)Decls here to create
   1328     // DW_TAG_imported_declarations inside the class for base decls brought into
   1329     // derived classes. GDB doesn't seem to notice/leverage these when I tried
   1330     // it, so I'm not rushing to fix this. (GCC seems to produce them, if
   1331     // referenced)
   1332     if (!Method || Method->isImplicit() || Method->hasAttr<NoDebugAttr>())
   1333       continue;
   1334 
   1335     if (Method->getType()->getAs<FunctionProtoType>()->getContainedAutoType())
   1336       continue;
   1337 
   1338     // Reuse the existing member function declaration if it exists.
   1339     // It may be associated with the declaration of the type & should be
   1340     // reused as we're building the definition.
   1341     //
   1342     // This situation can arise in the vtable-based debug info reduction where
   1343     // implicit members are emitted in a non-vtable TU.
   1344     auto MI = SPCache.find(Method->getCanonicalDecl());
   1345     EltTys.push_back(MI == SPCache.end()
   1346                          ? CreateCXXMemberFunction(Method, Unit, RecordTy)
   1347                          : static_cast<llvm::Metadata *>(MI->second));
   1348   }
   1349 }
   1350 
   1351 void CGDebugInfo::CollectCXXBases(const CXXRecordDecl *RD, llvm::DIFile *Unit,
   1352                                   SmallVectorImpl<llvm::Metadata *> &EltTys,
   1353                                   llvm::DIType *RecordTy) {
   1354   const ASTRecordLayout &RL = CGM.getContext().getASTRecordLayout(RD);
   1355   for (const auto &BI : RD->bases()) {
   1356     unsigned BFlags = 0;
   1357     uint64_t BaseOffset;
   1358 
   1359     const CXXRecordDecl *Base =
   1360         cast<CXXRecordDecl>(BI.getType()->getAs<RecordType>()->getDecl());
   1361 
   1362     if (BI.isVirtual()) {
   1363       if (CGM.getTarget().getCXXABI().isItaniumFamily()) {
   1364         // virtual base offset offset is -ve. The code generator emits dwarf
   1365         // expression where it expects +ve number.
   1366         BaseOffset = 0 - CGM.getItaniumVTableContext()
   1367                              .getVirtualBaseOffsetOffset(RD, Base)
   1368                              .getQuantity();
   1369       } else {
   1370         // In the MS ABI, store the vbtable offset, which is analogous to the
   1371         // vbase offset offset in Itanium.
   1372         BaseOffset =
   1373             4 * CGM.getMicrosoftVTableContext().getVBTableIndex(RD, Base);
   1374       }
   1375       BFlags = llvm::DINode::FlagVirtual;
   1376     } else
   1377       BaseOffset = CGM.getContext().toBits(RL.getBaseClassOffset(Base));
   1378     // FIXME: Inconsistent units for BaseOffset. It is in bytes when
   1379     // BI->isVirtual() and bits when not.
   1380 
   1381     BFlags |= getAccessFlag(BI.getAccessSpecifier(), RD);
   1382     llvm::DIType *DTy = DBuilder.createInheritance(
   1383         RecordTy, getOrCreateType(BI.getType(), Unit), BaseOffset, BFlags);
   1384     EltTys.push_back(DTy);
   1385   }
   1386 }
   1387 
   1388 llvm::DINodeArray
   1389 CGDebugInfo::CollectTemplateParams(const TemplateParameterList *TPList,
   1390                                    ArrayRef<TemplateArgument> TAList,
   1391                                    llvm::DIFile *Unit) {
   1392   SmallVector<llvm::Metadata *, 16> TemplateParams;
   1393   for (unsigned i = 0, e = TAList.size(); i != e; ++i) {
   1394     const TemplateArgument &TA = TAList[i];
   1395     StringRef Name;
   1396     if (TPList)
   1397       Name = TPList->getParam(i)->getName();
   1398     switch (TA.getKind()) {
   1399     case TemplateArgument::Type: {
   1400       llvm::DIType *TTy = getOrCreateType(TA.getAsType(), Unit);
   1401       TemplateParams.push_back(
   1402           DBuilder.createTemplateTypeParameter(TheCU, Name, TTy));
   1403     } break;
   1404     case TemplateArgument::Integral: {
   1405       llvm::DIType *TTy = getOrCreateType(TA.getIntegralType(), Unit);
   1406       TemplateParams.push_back(DBuilder.createTemplateValueParameter(
   1407           TheCU, Name, TTy,
   1408           llvm::ConstantInt::get(CGM.getLLVMContext(), TA.getAsIntegral())));
   1409     } break;
   1410     case TemplateArgument::Declaration: {
   1411       const ValueDecl *D = TA.getAsDecl();
   1412       QualType T = TA.getParamTypeForDecl().getDesugaredType(CGM.getContext());
   1413       llvm::DIType *TTy = getOrCreateType(T, Unit);
   1414       llvm::Constant *V = nullptr;
   1415       const CXXMethodDecl *MD;
   1416       // Variable pointer template parameters have a value that is the address
   1417       // of the variable.
   1418       if (const auto *VD = dyn_cast<VarDecl>(D))
   1419         V = CGM.GetAddrOfGlobalVar(VD);
   1420       // Member function pointers have special support for building them, though
   1421       // this is currently unsupported in LLVM CodeGen.
   1422       else if ((MD = dyn_cast<CXXMethodDecl>(D)) && MD->isInstance())
   1423         V = CGM.getCXXABI().EmitMemberFunctionPointer(MD);
   1424       else if (const auto *FD = dyn_cast<FunctionDecl>(D))
   1425         V = CGM.GetAddrOfFunction(FD);
   1426       // Member data pointers have special handling too to compute the fixed
   1427       // offset within the object.
   1428       else if (const auto *MPT = dyn_cast<MemberPointerType>(T.getTypePtr())) {
   1429         // These five lines (& possibly the above member function pointer
   1430         // handling) might be able to be refactored to use similar code in
   1431         // CodeGenModule::getMemberPointerConstant
   1432         uint64_t fieldOffset = CGM.getContext().getFieldOffset(D);
   1433         CharUnits chars =
   1434             CGM.getContext().toCharUnitsFromBits((int64_t)fieldOffset);
   1435         V = CGM.getCXXABI().EmitMemberDataPointer(MPT, chars);
   1436       }
   1437       TemplateParams.push_back(DBuilder.createTemplateValueParameter(
   1438           TheCU, Name, TTy,
   1439           cast_or_null<llvm::Constant>(V->stripPointerCasts())));
   1440     } break;
   1441     case TemplateArgument::NullPtr: {
   1442       QualType T = TA.getNullPtrType();
   1443       llvm::DIType *TTy = getOrCreateType(T, Unit);
   1444       llvm::Constant *V = nullptr;
   1445       // Special case member data pointer null values since they're actually -1
   1446       // instead of zero.
   1447       if (const MemberPointerType *MPT =
   1448               dyn_cast<MemberPointerType>(T.getTypePtr()))
   1449         // But treat member function pointers as simple zero integers because
   1450         // it's easier than having a special case in LLVM's CodeGen. If LLVM
   1451         // CodeGen grows handling for values of non-null member function
   1452         // pointers then perhaps we could remove this special case and rely on
   1453         // EmitNullMemberPointer for member function pointers.
   1454         if (MPT->isMemberDataPointer())
   1455           V = CGM.getCXXABI().EmitNullMemberPointer(MPT);
   1456       if (!V)
   1457         V = llvm::ConstantInt::get(CGM.Int8Ty, 0);
   1458       TemplateParams.push_back(DBuilder.createTemplateValueParameter(
   1459           TheCU, Name, TTy, cast<llvm::Constant>(V)));
   1460     } break;
   1461     case TemplateArgument::Template:
   1462       TemplateParams.push_back(DBuilder.createTemplateTemplateParameter(
   1463           TheCU, Name, nullptr,
   1464           TA.getAsTemplate().getAsTemplateDecl()->getQualifiedNameAsString()));
   1465       break;
   1466     case TemplateArgument::Pack:
   1467       TemplateParams.push_back(DBuilder.createTemplateParameterPack(
   1468           TheCU, Name, nullptr,
   1469           CollectTemplateParams(nullptr, TA.getPackAsArray(), Unit)));
   1470       break;
   1471     case TemplateArgument::Expression: {
   1472       const Expr *E = TA.getAsExpr();
   1473       QualType T = E->getType();
   1474       if (E->isGLValue())
   1475         T = CGM.getContext().getLValueReferenceType(T);
   1476       llvm::Constant *V = CGM.EmitConstantExpr(E, T);
   1477       assert(V && "Expression in template argument isn't constant");
   1478       llvm::DIType *TTy = getOrCreateType(T, Unit);
   1479       TemplateParams.push_back(DBuilder.createTemplateValueParameter(
   1480           TheCU, Name, TTy, cast<llvm::Constant>(V->stripPointerCasts())));
   1481     } break;
   1482     // And the following should never occur:
   1483     case TemplateArgument::TemplateExpansion:
   1484     case TemplateArgument::Null:
   1485       llvm_unreachable(
   1486           "These argument types shouldn't exist in concrete types");
   1487     }
   1488   }
   1489   return DBuilder.getOrCreateArray(TemplateParams);
   1490 }
   1491 
   1492 llvm::DINodeArray
   1493 CGDebugInfo::CollectFunctionTemplateParams(const FunctionDecl *FD,
   1494                                            llvm::DIFile *Unit) {
   1495   if (FD->getTemplatedKind() ==
   1496       FunctionDecl::TK_FunctionTemplateSpecialization) {
   1497     const TemplateParameterList *TList = FD->getTemplateSpecializationInfo()
   1498                                              ->getTemplate()
   1499                                              ->getTemplateParameters();
   1500     return CollectTemplateParams(
   1501         TList, FD->getTemplateSpecializationArgs()->asArray(), Unit);
   1502   }
   1503   return llvm::DINodeArray();
   1504 }
   1505 
   1506 llvm::DINodeArray CGDebugInfo::CollectCXXTemplateParams(
   1507     const ClassTemplateSpecializationDecl *TSpecial, llvm::DIFile *Unit) {
   1508   // Always get the full list of parameters, not just the ones from
   1509   // the specialization.
   1510   TemplateParameterList *TPList =
   1511       TSpecial->getSpecializedTemplate()->getTemplateParameters();
   1512   const TemplateArgumentList &TAList = TSpecial->getTemplateArgs();
   1513   return CollectTemplateParams(TPList, TAList.asArray(), Unit);
   1514 }
   1515 
   1516 llvm::DIType *CGDebugInfo::getOrCreateVTablePtrType(llvm::DIFile *Unit) {
   1517   if (VTablePtrType)
   1518     return VTablePtrType;
   1519 
   1520   ASTContext &Context = CGM.getContext();
   1521 
   1522   /* Function type */
   1523   llvm::Metadata *STy = getOrCreateType(Context.IntTy, Unit);
   1524   llvm::DITypeRefArray SElements = DBuilder.getOrCreateTypeArray(STy);
   1525   llvm::DIType *SubTy = DBuilder.createSubroutineType(SElements);
   1526   unsigned Size = Context.getTypeSize(Context.VoidPtrTy);
   1527   llvm::DIType *vtbl_ptr_type =
   1528       DBuilder.createPointerType(SubTy, Size, 0, "__vtbl_ptr_type");
   1529   VTablePtrType = DBuilder.createPointerType(vtbl_ptr_type, Size);
   1530   return VTablePtrType;
   1531 }
   1532 
   1533 StringRef CGDebugInfo::getVTableName(const CXXRecordDecl *RD) {
   1534   // Copy the gdb compatible name on the side and use its reference.
   1535   return internString("_vptr$", RD->getNameAsString());
   1536 }
   1537 
   1538 void CGDebugInfo::CollectVTableInfo(const CXXRecordDecl *RD, llvm::DIFile *Unit,
   1539                                     SmallVectorImpl<llvm::Metadata *> &EltTys) {
   1540   const ASTRecordLayout &RL = CGM.getContext().getASTRecordLayout(RD);
   1541 
   1542   // If there is a primary base then it will hold vtable info.
   1543   if (RL.getPrimaryBase())
   1544     return;
   1545 
   1546   // If this class is not dynamic then there is not any vtable info to collect.
   1547   if (!RD->isDynamicClass())
   1548     return;
   1549 
   1550   unsigned Size = CGM.getContext().getTypeSize(CGM.getContext().VoidPtrTy);
   1551   llvm::DIType *VPTR = DBuilder.createMemberType(
   1552       Unit, getVTableName(RD), Unit, 0, Size, 0, 0,
   1553       llvm::DINode::FlagArtificial, getOrCreateVTablePtrType(Unit));
   1554   EltTys.push_back(VPTR);
   1555 }
   1556 
   1557 llvm::DIType *CGDebugInfo::getOrCreateRecordType(QualType RTy,
   1558                                                  SourceLocation Loc) {
   1559   assert(DebugKind >= codegenoptions::LimitedDebugInfo);
   1560   llvm::DIType *T = getOrCreateType(RTy, getOrCreateFile(Loc));
   1561   return T;
   1562 }
   1563 
   1564 llvm::DIType *CGDebugInfo::getOrCreateInterfaceType(QualType D,
   1565                                                     SourceLocation Loc) {
   1566   return getOrCreateStandaloneType(D, Loc);
   1567 }
   1568 
   1569 llvm::DIType *CGDebugInfo::getOrCreateStandaloneType(QualType D,
   1570                                                      SourceLocation Loc) {
   1571   assert(DebugKind >= codegenoptions::LimitedDebugInfo);
   1572   assert(!D.isNull() && "null type");
   1573   llvm::DIType *T = getOrCreateType(D, getOrCreateFile(Loc));
   1574   assert(T && "could not create debug info for type");
   1575 
   1576   RetainedTypes.push_back(D.getAsOpaquePtr());
   1577   return T;
   1578 }
   1579 
   1580 void CGDebugInfo::completeType(const EnumDecl *ED) {
   1581   if (DebugKind <= codegenoptions::DebugLineTablesOnly)
   1582     return;
   1583   QualType Ty = CGM.getContext().getEnumType(ED);
   1584   void *TyPtr = Ty.getAsOpaquePtr();
   1585   auto I = TypeCache.find(TyPtr);
   1586   if (I == TypeCache.end() || !cast<llvm::DIType>(I->second)->isForwardDecl())
   1587     return;
   1588   llvm::DIType *Res = CreateTypeDefinition(Ty->castAs<EnumType>());
   1589   assert(!Res->isForwardDecl());
   1590   TypeCache[TyPtr].reset(Res);
   1591 }
   1592 
   1593 void CGDebugInfo::completeType(const RecordDecl *RD) {
   1594   if (DebugKind > codegenoptions::LimitedDebugInfo ||
   1595       !CGM.getLangOpts().CPlusPlus)
   1596     completeRequiredType(RD);
   1597 }
   1598 
   1599 void CGDebugInfo::completeRequiredType(const RecordDecl *RD) {
   1600   if (DebugKind <= codegenoptions::DebugLineTablesOnly)
   1601     return;
   1602 
   1603   if (const CXXRecordDecl *CXXDecl = dyn_cast<CXXRecordDecl>(RD))
   1604     if (CXXDecl->isDynamicClass())
   1605       return;
   1606 
   1607   if (DebugTypeExtRefs && RD->isFromASTFile())
   1608     return;
   1609 
   1610   QualType Ty = CGM.getContext().getRecordType(RD);
   1611   llvm::DIType *T = getTypeOrNull(Ty);
   1612   if (T && T->isForwardDecl())
   1613     completeClassData(RD);
   1614 }
   1615 
   1616 void CGDebugInfo::completeClassData(const RecordDecl *RD) {
   1617   if (DebugKind <= codegenoptions::DebugLineTablesOnly)
   1618     return;
   1619   QualType Ty = CGM.getContext().getRecordType(RD);
   1620   void *TyPtr = Ty.getAsOpaquePtr();
   1621   auto I = TypeCache.find(TyPtr);
   1622   if (I != TypeCache.end() && !cast<llvm::DIType>(I->second)->isForwardDecl())
   1623     return;
   1624   llvm::DIType *Res = CreateTypeDefinition(Ty->castAs<RecordType>());
   1625   assert(!Res->isForwardDecl());
   1626   TypeCache[TyPtr].reset(Res);
   1627 }
   1628 
   1629 static bool hasExplicitMemberDefinition(CXXRecordDecl::method_iterator I,
   1630                                         CXXRecordDecl::method_iterator End) {
   1631   for (; I != End; ++I)
   1632     if (FunctionDecl *Tmpl = I->getInstantiatedFromMemberFunction())
   1633       if (!Tmpl->isImplicit() && Tmpl->isThisDeclarationADefinition() &&
   1634           !I->getMemberSpecializationInfo()->isExplicitSpecialization())
   1635         return true;
   1636   return false;
   1637 }
   1638 
   1639 /// Does a type definition exist in an imported clang module?
   1640 static bool isDefinedInClangModule(const RecordDecl *RD) {
   1641   if (!RD || !RD->isFromASTFile())
   1642     return false;
   1643   if (!RD->isExternallyVisible() && RD->getName().empty())
   1644     return false;
   1645   if (auto *CXXDecl = dyn_cast<CXXRecordDecl>(RD)) {
   1646     assert(CXXDecl->isCompleteDefinition() && "incomplete record definition");
   1647     if (CXXDecl->getTemplateSpecializationKind() != TSK_Undeclared)
   1648       // Make sure the instantiation is actually in a module.
   1649       if (CXXDecl->field_begin() != CXXDecl->field_end())
   1650         return CXXDecl->field_begin()->isFromASTFile();
   1651   }
   1652 
   1653   return true;
   1654 }
   1655 
   1656 static bool shouldOmitDefinition(codegenoptions::DebugInfoKind DebugKind,
   1657                                  bool DebugTypeExtRefs, const RecordDecl *RD,
   1658                                  const LangOptions &LangOpts) {
   1659   if (DebugTypeExtRefs && isDefinedInClangModule(RD->getDefinition()))
   1660     return true;
   1661 
   1662   if (DebugKind > codegenoptions::LimitedDebugInfo)
   1663     return false;
   1664 
   1665   if (!LangOpts.CPlusPlus)
   1666     return false;
   1667 
   1668   if (!RD->isCompleteDefinitionRequired())
   1669     return true;
   1670 
   1671   const CXXRecordDecl *CXXDecl = dyn_cast<CXXRecordDecl>(RD);
   1672 
   1673   if (!CXXDecl)
   1674     return false;
   1675 
   1676   if (CXXDecl->hasDefinition() && CXXDecl->isDynamicClass())
   1677     return true;
   1678 
   1679   TemplateSpecializationKind Spec = TSK_Undeclared;
   1680   if (const ClassTemplateSpecializationDecl *SD =
   1681           dyn_cast<ClassTemplateSpecializationDecl>(RD))
   1682     Spec = SD->getSpecializationKind();
   1683 
   1684   if (Spec == TSK_ExplicitInstantiationDeclaration &&
   1685       hasExplicitMemberDefinition(CXXDecl->method_begin(),
   1686                                   CXXDecl->method_end()))
   1687     return true;
   1688 
   1689   return false;
   1690 }
   1691 
   1692 llvm::DIType *CGDebugInfo::CreateType(const RecordType *Ty) {
   1693   RecordDecl *RD = Ty->getDecl();
   1694   llvm::DIType *T = cast_or_null<llvm::DIType>(getTypeOrNull(QualType(Ty, 0)));
   1695   if (T || shouldOmitDefinition(DebugKind, DebugTypeExtRefs, RD,
   1696                                 CGM.getLangOpts())) {
   1697     if (!T)
   1698       T = getOrCreateRecordFwdDecl(Ty, getDeclContextDescriptor(RD));
   1699     return T;
   1700   }
   1701 
   1702   return CreateTypeDefinition(Ty);
   1703 }
   1704 
   1705 llvm::DIType *CGDebugInfo::CreateTypeDefinition(const RecordType *Ty) {
   1706   RecordDecl *RD = Ty->getDecl();
   1707 
   1708   // Get overall information about the record type for the debug info.
   1709   llvm::DIFile *DefUnit = getOrCreateFile(RD->getLocation());
   1710 
   1711   // Records and classes and unions can all be recursive.  To handle them, we
   1712   // first generate a debug descriptor for the struct as a forward declaration.
   1713   // Then (if it is a definition) we go through and get debug info for all of
   1714   // its members.  Finally, we create a descriptor for the complete type (which
   1715   // may refer to the forward decl if the struct is recursive) and replace all
   1716   // uses of the forward declaration with the final definition.
   1717   llvm::DICompositeType *FwdDecl = getOrCreateLimitedType(Ty, DefUnit);
   1718 
   1719   const RecordDecl *D = RD->getDefinition();
   1720   if (!D || !D->isCompleteDefinition())
   1721     return FwdDecl;
   1722 
   1723   if (const CXXRecordDecl *CXXDecl = dyn_cast<CXXRecordDecl>(RD))
   1724     CollectContainingType(CXXDecl, FwdDecl);
   1725 
   1726   // Push the struct on region stack.
   1727   LexicalBlockStack.emplace_back(&*FwdDecl);
   1728   RegionMap[Ty->getDecl()].reset(FwdDecl);
   1729 
   1730   // Convert all the elements.
   1731   SmallVector<llvm::Metadata *, 16> EltTys;
   1732   // what about nested types?
   1733 
   1734   // Note: The split of CXXDecl information here is intentional, the
   1735   // gdb tests will depend on a certain ordering at printout. The debug
   1736   // information offsets are still correct if we merge them all together
   1737   // though.
   1738   const CXXRecordDecl *CXXDecl = dyn_cast<CXXRecordDecl>(RD);
   1739   if (CXXDecl) {
   1740     CollectCXXBases(CXXDecl, DefUnit, EltTys, FwdDecl);
   1741     CollectVTableInfo(CXXDecl, DefUnit, EltTys);
   1742   }
   1743 
   1744   // Collect data fields (including static variables and any initializers).
   1745   CollectRecordFields(RD, DefUnit, EltTys, FwdDecl);
   1746   if (CXXDecl)
   1747     CollectCXXMemberFunctions(CXXDecl, DefUnit, EltTys, FwdDecl);
   1748 
   1749   LexicalBlockStack.pop_back();
   1750   RegionMap.erase(Ty->getDecl());
   1751 
   1752   llvm::DINodeArray Elements = DBuilder.getOrCreateArray(EltTys);
   1753   DBuilder.replaceArrays(FwdDecl, Elements);
   1754 
   1755   if (FwdDecl->isTemporary())
   1756     FwdDecl =
   1757         llvm::MDNode::replaceWithPermanent(llvm::TempDICompositeType(FwdDecl));
   1758 
   1759   RegionMap[Ty->getDecl()].reset(FwdDecl);
   1760   return FwdDecl;
   1761 }
   1762 
   1763 llvm::DIType *CGDebugInfo::CreateType(const ObjCObjectType *Ty,
   1764                                       llvm::DIFile *Unit) {
   1765   // Ignore protocols.
   1766   return getOrCreateType(Ty->getBaseType(), Unit);
   1767 }
   1768 
   1769 /// \return true if Getter has the default name for the property PD.
   1770 static bool hasDefaultGetterName(const ObjCPropertyDecl *PD,
   1771                                  const ObjCMethodDecl *Getter) {
   1772   assert(PD);
   1773   if (!Getter)
   1774     return true;
   1775 
   1776   assert(Getter->getDeclName().isObjCZeroArgSelector());
   1777   return PD->getName() ==
   1778          Getter->getDeclName().getObjCSelector().getNameForSlot(0);
   1779 }
   1780 
   1781 /// \return true if Setter has the default name for the property PD.
   1782 static bool hasDefaultSetterName(const ObjCPropertyDecl *PD,
   1783                                  const ObjCMethodDecl *Setter) {
   1784   assert(PD);
   1785   if (!Setter)
   1786     return true;
   1787 
   1788   assert(Setter->getDeclName().isObjCOneArgSelector());
   1789   return SelectorTable::constructSetterName(PD->getName()) ==
   1790          Setter->getDeclName().getObjCSelector().getNameForSlot(0);
   1791 }
   1792 
   1793 llvm::DIType *CGDebugInfo::CreateType(const ObjCInterfaceType *Ty,
   1794                                       llvm::DIFile *Unit) {
   1795   ObjCInterfaceDecl *ID = Ty->getDecl();
   1796   if (!ID)
   1797     return nullptr;
   1798 
   1799   // Return a forward declaration if this type was imported from a clang module,
   1800   // and this is not the compile unit with the implementation of the type (which
   1801   // may contain hidden ivars).
   1802   if (DebugTypeExtRefs && ID->isFromASTFile() && ID->getDefinition() &&
   1803       !ID->getImplementation())
   1804     return DBuilder.createForwardDecl(llvm::dwarf::DW_TAG_structure_type,
   1805                                       ID->getName(),
   1806                                       getDeclContextDescriptor(ID), Unit, 0);
   1807 
   1808   // Get overall information about the record type for the debug info.
   1809   llvm::DIFile *DefUnit = getOrCreateFile(ID->getLocation());
   1810   unsigned Line = getLineNumber(ID->getLocation());
   1811   auto RuntimeLang =
   1812       static_cast<llvm::dwarf::SourceLanguage>(TheCU->getSourceLanguage());
   1813 
   1814   // If this is just a forward declaration return a special forward-declaration
   1815   // debug type since we won't be able to lay out the entire type.
   1816   ObjCInterfaceDecl *Def = ID->getDefinition();
   1817   if (!Def || !Def->getImplementation()) {
   1818     llvm::DIScope *Mod = getParentModuleOrNull(ID);
   1819     llvm::DIType *FwdDecl = DBuilder.createReplaceableCompositeType(
   1820         llvm::dwarf::DW_TAG_structure_type, ID->getName(), Mod ? Mod : TheCU,
   1821         DefUnit, Line, RuntimeLang);
   1822     ObjCInterfaceCache.push_back(ObjCInterfaceCacheEntry(Ty, FwdDecl, Unit));
   1823     return FwdDecl;
   1824   }
   1825 
   1826   return CreateTypeDefinition(Ty, Unit);
   1827 }
   1828 
   1829 llvm::DIModule *
   1830 CGDebugInfo::getOrCreateModuleRef(ExternalASTSource::ASTSourceDescriptor Mod,
   1831                                   bool CreateSkeletonCU) {
   1832   // Use the Module pointer as the key into the cache. This is a
   1833   // nullptr if the "Module" is a PCH, which is safe because we don't
   1834   // support chained PCH debug info, so there can only be a single PCH.
   1835   const Module *M = Mod.getModuleOrNull();
   1836   auto ModRef = ModuleCache.find(M);
   1837   if (ModRef != ModuleCache.end())
   1838     return cast<llvm::DIModule>(ModRef->second);
   1839 
   1840   // Macro definitions that were defined with "-D" on the command line.
   1841   SmallString<128> ConfigMacros;
   1842   {
   1843     llvm::raw_svector_ostream OS(ConfigMacros);
   1844     const auto &PPOpts = CGM.getPreprocessorOpts();
   1845     unsigned I = 0;
   1846     // Translate the macro definitions back into a commmand line.
   1847     for (auto &M : PPOpts.Macros) {
   1848       if (++I > 1)
   1849         OS << " ";
   1850       const std::string &Macro = M.first;
   1851       bool Undef = M.second;
   1852       OS << "\"-" << (Undef ? 'U' : 'D');
   1853       for (char c : Macro)
   1854         switch (c) {
   1855         case '\\' : OS << "\\\\"; break;
   1856         case '"'  : OS << "\\\""; break;
   1857         default: OS << c;
   1858         }
   1859       OS << '\"';
   1860     }
   1861   }
   1862 
   1863   bool IsRootModule = M ? !M->Parent : true;
   1864   if (CreateSkeletonCU && IsRootModule) {
   1865     // PCH files don't have a signature field in the control block,
   1866     // but LLVM detects skeleton CUs by looking for a non-zero DWO id.
   1867     uint64_t Signature = Mod.getSignature() ? Mod.getSignature() : ~1ULL;
   1868     llvm::DIBuilder DIB(CGM.getModule());
   1869     DIB.createCompileUnit(TheCU->getSourceLanguage(), Mod.getModuleName(),
   1870                           Mod.getPath(), TheCU->getProducer(), true,
   1871                           StringRef(), 0, Mod.getASTFile(),
   1872                           llvm::DICompileUnit::FullDebug, Signature);
   1873     DIB.finalize();
   1874   }
   1875   llvm::DIModule *Parent =
   1876       IsRootModule ? nullptr
   1877                    : getOrCreateModuleRef(
   1878                          ExternalASTSource::ASTSourceDescriptor(*M->Parent),
   1879                          CreateSkeletonCU);
   1880   llvm::DIModule *DIMod =
   1881       DBuilder.createModule(Parent, Mod.getModuleName(), ConfigMacros,
   1882                             Mod.getPath(), CGM.getHeaderSearchOpts().Sysroot);
   1883   ModuleCache[M].reset(DIMod);
   1884   return DIMod;
   1885 }
   1886 
   1887 llvm::DIType *CGDebugInfo::CreateTypeDefinition(const ObjCInterfaceType *Ty,
   1888                                                 llvm::DIFile *Unit) {
   1889   ObjCInterfaceDecl *ID = Ty->getDecl();
   1890   llvm::DIFile *DefUnit = getOrCreateFile(ID->getLocation());
   1891   unsigned Line = getLineNumber(ID->getLocation());
   1892   unsigned RuntimeLang = TheCU->getSourceLanguage();
   1893 
   1894   // Bit size, align and offset of the type.
   1895   uint64_t Size = CGM.getContext().getTypeSize(Ty);
   1896   uint64_t Align = CGM.getContext().getTypeAlign(Ty);
   1897 
   1898   unsigned Flags = 0;
   1899   if (ID->getImplementation())
   1900     Flags |= llvm::DINode::FlagObjcClassComplete;
   1901 
   1902   llvm::DIScope *Mod = getParentModuleOrNull(ID);
   1903   llvm::DICompositeType *RealDecl = DBuilder.createStructType(
   1904       Mod ? Mod : Unit, ID->getName(), DefUnit, Line, Size, Align, Flags,
   1905       nullptr, llvm::DINodeArray(), RuntimeLang);
   1906 
   1907   QualType QTy(Ty, 0);
   1908   TypeCache[QTy.getAsOpaquePtr()].reset(RealDecl);
   1909 
   1910   // Push the struct on region stack.
   1911   LexicalBlockStack.emplace_back(RealDecl);
   1912   RegionMap[Ty->getDecl()].reset(RealDecl);
   1913 
   1914   // Convert all the elements.
   1915   SmallVector<llvm::Metadata *, 16> EltTys;
   1916 
   1917   ObjCInterfaceDecl *SClass = ID->getSuperClass();
   1918   if (SClass) {
   1919     llvm::DIType *SClassTy =
   1920         getOrCreateType(CGM.getContext().getObjCInterfaceType(SClass), Unit);
   1921     if (!SClassTy)
   1922       return nullptr;
   1923 
   1924     llvm::DIType *InhTag = DBuilder.createInheritance(RealDecl, SClassTy, 0, 0);
   1925     EltTys.push_back(InhTag);
   1926   }
   1927 
   1928   // Create entries for all of the properties.
   1929   auto AddProperty = [&](const ObjCPropertyDecl *PD) {
   1930     SourceLocation Loc = PD->getLocation();
   1931     llvm::DIFile *PUnit = getOrCreateFile(Loc);
   1932     unsigned PLine = getLineNumber(Loc);
   1933     ObjCMethodDecl *Getter = PD->getGetterMethodDecl();
   1934     ObjCMethodDecl *Setter = PD->getSetterMethodDecl();
   1935     llvm::MDNode *PropertyNode = DBuilder.createObjCProperty(
   1936         PD->getName(), PUnit, PLine,
   1937         hasDefaultGetterName(PD, Getter) ? ""
   1938                                          : getSelectorName(PD->getGetterName()),
   1939         hasDefaultSetterName(PD, Setter) ? ""
   1940                                          : getSelectorName(PD->getSetterName()),
   1941         PD->getPropertyAttributes(), getOrCreateType(PD->getType(), PUnit));
   1942     EltTys.push_back(PropertyNode);
   1943   };
   1944   {
   1945     llvm::SmallPtrSet<const IdentifierInfo*, 16> PropertySet;
   1946     for (const ObjCCategoryDecl *ClassExt : ID->known_extensions())
   1947       for (auto *PD : ClassExt->properties()) {
   1948         PropertySet.insert(PD->getIdentifier());
   1949         AddProperty(PD);
   1950       }
   1951     for (const auto *PD : ID->properties()) {
   1952       // Don't emit duplicate metadata for properties that were already in a
   1953       // class extension.
   1954       if (!PropertySet.insert(PD->getIdentifier()).second)
   1955         continue;
   1956       AddProperty(PD);
   1957     }
   1958   }
   1959 
   1960   const ASTRecordLayout &RL = CGM.getContext().getASTObjCInterfaceLayout(ID);
   1961   unsigned FieldNo = 0;
   1962   for (ObjCIvarDecl *Field = ID->all_declared_ivar_begin(); Field;
   1963        Field = Field->getNextIvar(), ++FieldNo) {
   1964     llvm::DIType *FieldTy = getOrCreateType(Field->getType(), Unit);
   1965     if (!FieldTy)
   1966       return nullptr;
   1967 
   1968     StringRef FieldName = Field->getName();
   1969 
   1970     // Ignore unnamed fields.
   1971     if (FieldName.empty())
   1972       continue;
   1973 
   1974     // Get the location for the field.
   1975     llvm::DIFile *FieldDefUnit = getOrCreateFile(Field->getLocation());
   1976     unsigned FieldLine = getLineNumber(Field->getLocation());
   1977     QualType FType = Field->getType();
   1978     uint64_t FieldSize = 0;
   1979     unsigned FieldAlign = 0;
   1980 
   1981     if (!FType->isIncompleteArrayType()) {
   1982 
   1983       // Bit size, align and offset of the type.
   1984       FieldSize = Field->isBitField()
   1985                       ? Field->getBitWidthValue(CGM.getContext())
   1986                       : CGM.getContext().getTypeSize(FType);
   1987       FieldAlign = CGM.getContext().getTypeAlign(FType);
   1988     }
   1989 
   1990     uint64_t FieldOffset;
   1991     if (CGM.getLangOpts().ObjCRuntime.isNonFragile()) {
   1992       // We don't know the runtime offset of an ivar if we're using the
   1993       // non-fragile ABI.  For bitfields, use the bit offset into the first
   1994       // byte of storage of the bitfield.  For other fields, use zero.
   1995       if (Field->isBitField()) {
   1996         FieldOffset =
   1997             CGM.getObjCRuntime().ComputeBitfieldBitOffset(CGM, ID, Field);
   1998         FieldOffset %= CGM.getContext().getCharWidth();
   1999       } else {
   2000         FieldOffset = 0;
   2001       }
   2002     } else {
   2003       FieldOffset = RL.getFieldOffset(FieldNo);
   2004     }
   2005 
   2006     unsigned Flags = 0;
   2007     if (Field->getAccessControl() == ObjCIvarDecl::Protected)
   2008       Flags = llvm::DINode::FlagProtected;
   2009     else if (Field->getAccessControl() == ObjCIvarDecl::Private)
   2010       Flags = llvm::DINode::FlagPrivate;
   2011     else if (Field->getAccessControl() == ObjCIvarDecl::Public)
   2012       Flags = llvm::DINode::FlagPublic;
   2013 
   2014     llvm::MDNode *PropertyNode = nullptr;
   2015     if (ObjCImplementationDecl *ImpD = ID->getImplementation()) {
   2016       if (ObjCPropertyImplDecl *PImpD =
   2017               ImpD->FindPropertyImplIvarDecl(Field->getIdentifier())) {
   2018         if (ObjCPropertyDecl *PD = PImpD->getPropertyDecl()) {
   2019           SourceLocation Loc = PD->getLocation();
   2020           llvm::DIFile *PUnit = getOrCreateFile(Loc);
   2021           unsigned PLine = getLineNumber(Loc);
   2022           ObjCMethodDecl *Getter = PD->getGetterMethodDecl();
   2023           ObjCMethodDecl *Setter = PD->getSetterMethodDecl();
   2024           PropertyNode = DBuilder.createObjCProperty(
   2025               PD->getName(), PUnit, PLine,
   2026               hasDefaultGetterName(PD, Getter) ? "" : getSelectorName(
   2027                                                           PD->getGetterName()),
   2028               hasDefaultSetterName(PD, Setter) ? "" : getSelectorName(
   2029                                                           PD->getSetterName()),
   2030               PD->getPropertyAttributes(),
   2031               getOrCreateType(PD->getType(), PUnit));
   2032         }
   2033       }
   2034     }
   2035     FieldTy = DBuilder.createObjCIVar(FieldName, FieldDefUnit, FieldLine,
   2036                                       FieldSize, FieldAlign, FieldOffset, Flags,
   2037                                       FieldTy, PropertyNode);
   2038     EltTys.push_back(FieldTy);
   2039   }
   2040 
   2041   llvm::DINodeArray Elements = DBuilder.getOrCreateArray(EltTys);
   2042   DBuilder.replaceArrays(RealDecl, Elements);
   2043 
   2044   LexicalBlockStack.pop_back();
   2045   return RealDecl;
   2046 }
   2047 
   2048 llvm::DIType *CGDebugInfo::CreateType(const VectorType *Ty,
   2049                                       llvm::DIFile *Unit) {
   2050   llvm::DIType *ElementTy = getOrCreateType(Ty->getElementType(), Unit);
   2051   int64_t Count = Ty->getNumElements();
   2052   if (Count == 0)
   2053     // If number of elements are not known then this is an unbounded array.
   2054     // Use Count == -1 to express such arrays.
   2055     Count = -1;
   2056 
   2057   llvm::Metadata *Subscript = DBuilder.getOrCreateSubrange(0, Count);
   2058   llvm::DINodeArray SubscriptArray = DBuilder.getOrCreateArray(Subscript);
   2059 
   2060   uint64_t Size = CGM.getContext().getTypeSize(Ty);
   2061   uint64_t Align = CGM.getContext().getTypeAlign(Ty);
   2062 
   2063   return DBuilder.createVectorType(Size, Align, ElementTy, SubscriptArray);
   2064 }
   2065 
   2066 llvm::DIType *CGDebugInfo::CreateType(const ArrayType *Ty, llvm::DIFile *Unit) {
   2067   uint64_t Size;
   2068   uint64_t Align;
   2069 
   2070   // FIXME: make getTypeAlign() aware of VLAs and incomplete array types
   2071   if (const VariableArrayType *VAT = dyn_cast<VariableArrayType>(Ty)) {
   2072     Size = 0;
   2073     Align =
   2074         CGM.getContext().getTypeAlign(CGM.getContext().getBaseElementType(VAT));
   2075   } else if (Ty->isIncompleteArrayType()) {
   2076     Size = 0;
   2077     if (Ty->getElementType()->isIncompleteType())
   2078       Align = 0;
   2079     else
   2080       Align = CGM.getContext().getTypeAlign(Ty->getElementType());
   2081   } else if (Ty->isIncompleteType()) {
   2082     Size = 0;
   2083     Align = 0;
   2084   } else {
   2085     // Size and align of the whole array, not the element type.
   2086     Size = CGM.getContext().getTypeSize(Ty);
   2087     Align = CGM.getContext().getTypeAlign(Ty);
   2088   }
   2089 
   2090   // Add the dimensions of the array.  FIXME: This loses CV qualifiers from
   2091   // interior arrays, do we care?  Why aren't nested arrays represented the
   2092   // obvious/recursive way?
   2093   SmallVector<llvm::Metadata *, 8> Subscripts;
   2094   QualType EltTy(Ty, 0);
   2095   while ((Ty = dyn_cast<ArrayType>(EltTy))) {
   2096     // If the number of elements is known, then count is that number. Otherwise,
   2097     // it's -1. This allows us to represent a subrange with an array of 0
   2098     // elements, like this:
   2099     //
   2100     //   struct foo {
   2101     //     int x[0];
   2102     //   };
   2103     int64_t Count = -1; // Count == -1 is an unbounded array.
   2104     if (const ConstantArrayType *CAT = dyn_cast<ConstantArrayType>(Ty))
   2105       Count = CAT->getSize().getZExtValue();
   2106 
   2107     // FIXME: Verify this is right for VLAs.
   2108     Subscripts.push_back(DBuilder.getOrCreateSubrange(0, Count));
   2109     EltTy = Ty->getElementType();
   2110   }
   2111 
   2112   llvm::DINodeArray SubscriptArray = DBuilder.getOrCreateArray(Subscripts);
   2113 
   2114   return DBuilder.createArrayType(Size, Align, getOrCreateType(EltTy, Unit),
   2115                                   SubscriptArray);
   2116 }
   2117 
   2118 llvm::DIType *CGDebugInfo::CreateType(const LValueReferenceType *Ty,
   2119                                       llvm::DIFile *Unit) {
   2120   return CreatePointerLikeType(llvm::dwarf::DW_TAG_reference_type, Ty,
   2121                                Ty->getPointeeType(), Unit);
   2122 }
   2123 
   2124 llvm::DIType *CGDebugInfo::CreateType(const RValueReferenceType *Ty,
   2125                                       llvm::DIFile *Unit) {
   2126   return CreatePointerLikeType(llvm::dwarf::DW_TAG_rvalue_reference_type, Ty,
   2127                                Ty->getPointeeType(), Unit);
   2128 }
   2129 
   2130 llvm::DIType *CGDebugInfo::CreateType(const MemberPointerType *Ty,
   2131                                       llvm::DIFile *U) {
   2132   unsigned Flags = 0;
   2133   uint64_t Size = 0;
   2134 
   2135   if (!Ty->isIncompleteType()) {
   2136     Size = CGM.getContext().getTypeSize(Ty);
   2137 
   2138     // Set the MS inheritance model. There is no flag for the unspecified model.
   2139     if (CGM.getTarget().getCXXABI().isMicrosoft()) {
   2140       switch (Ty->getMostRecentCXXRecordDecl()->getMSInheritanceModel()) {
   2141       case MSInheritanceAttr::Keyword_single_inheritance:
   2142         Flags |= llvm::DINode::FlagSingleInheritance;
   2143         break;
   2144       case MSInheritanceAttr::Keyword_multiple_inheritance:
   2145         Flags |= llvm::DINode::FlagMultipleInheritance;
   2146         break;
   2147       case MSInheritanceAttr::Keyword_virtual_inheritance:
   2148         Flags |= llvm::DINode::FlagVirtualInheritance;
   2149         break;
   2150       case MSInheritanceAttr::Keyword_unspecified_inheritance:
   2151         break;
   2152       }
   2153     }
   2154   }
   2155 
   2156   llvm::DIType *ClassType = getOrCreateType(QualType(Ty->getClass(), 0), U);
   2157   if (Ty->isMemberDataPointerType())
   2158     return DBuilder.createMemberPointerType(
   2159         getOrCreateType(Ty->getPointeeType(), U), ClassType, Size, /*Align=*/0,
   2160         Flags);
   2161 
   2162   const FunctionProtoType *FPT =
   2163       Ty->getPointeeType()->getAs<FunctionProtoType>();
   2164   return DBuilder.createMemberPointerType(
   2165       getOrCreateInstanceMethodType(CGM.getContext().getPointerType(QualType(
   2166                                         Ty->getClass(), FPT->getTypeQuals())),
   2167                                     FPT, U),
   2168       ClassType, Size, /*Align=*/0, Flags);
   2169 }
   2170 
   2171 llvm::DIType *CGDebugInfo::CreateType(const AtomicType *Ty, llvm::DIFile *U) {
   2172   // Ignore the atomic wrapping
   2173   // FIXME: What is the correct representation?
   2174   return getOrCreateType(Ty->getValueType(), U);
   2175 }
   2176 
   2177 llvm::DIType* CGDebugInfo::CreateType(const PipeType *Ty,
   2178                                      llvm::DIFile *U) {
   2179   return getOrCreateType(Ty->getElementType(), U);
   2180 }
   2181 
   2182 llvm::DIType *CGDebugInfo::CreateEnumType(const EnumType *Ty) {
   2183   const EnumDecl *ED = Ty->getDecl();
   2184 
   2185   uint64_t Size = 0;
   2186   uint64_t Align = 0;
   2187   if (!ED->getTypeForDecl()->isIncompleteType()) {
   2188     Size = CGM.getContext().getTypeSize(ED->getTypeForDecl());
   2189     Align = CGM.getContext().getTypeAlign(ED->getTypeForDecl());
   2190   }
   2191 
   2192   SmallString<256> FullName = getUniqueTagTypeName(Ty, CGM, TheCU);
   2193 
   2194   bool isImportedFromModule =
   2195       DebugTypeExtRefs && ED->isFromASTFile() && ED->getDefinition();
   2196 
   2197   // If this is just a forward declaration, construct an appropriately
   2198   // marked node and just return it.
   2199   if (isImportedFromModule || !ED->getDefinition()) {
   2200     // Note that it is possible for enums to be created as part of
   2201     // their own declcontext. In this case a FwdDecl will be created
   2202     // twice. This doesn't cause a problem because both FwdDecls are
   2203     // entered into the ReplaceMap: finalize() will replace the first
   2204     // FwdDecl with the second and then replace the second with
   2205     // complete type.
   2206     llvm::DIScope *EDContext = getDeclContextDescriptor(ED);
   2207     llvm::DIFile *DefUnit = getOrCreateFile(ED->getLocation());
   2208     llvm::TempDIScope TmpContext(DBuilder.createReplaceableCompositeType(
   2209         llvm::dwarf::DW_TAG_enumeration_type, "", TheCU, DefUnit, 0));
   2210 
   2211     unsigned Line = getLineNumber(ED->getLocation());
   2212     StringRef EDName = ED->getName();
   2213     llvm::DIType *RetTy = DBuilder.createReplaceableCompositeType(
   2214         llvm::dwarf::DW_TAG_enumeration_type, EDName, EDContext, DefUnit, Line,
   2215         0, Size, Align, llvm::DINode::FlagFwdDecl, FullName);
   2216 
   2217     ReplaceMap.emplace_back(
   2218         std::piecewise_construct, std::make_tuple(Ty),
   2219         std::make_tuple(static_cast<llvm::Metadata *>(RetTy)));
   2220     return RetTy;
   2221   }
   2222 
   2223   return CreateTypeDefinition(Ty);
   2224 }
   2225 
   2226 llvm::DIType *CGDebugInfo::CreateTypeDefinition(const EnumType *Ty) {
   2227   const EnumDecl *ED = Ty->getDecl();
   2228   uint64_t Size = 0;
   2229   uint64_t Align = 0;
   2230   if (!ED->getTypeForDecl()->isIncompleteType()) {
   2231     Size = CGM.getContext().getTypeSize(ED->getTypeForDecl());
   2232     Align = CGM.getContext().getTypeAlign(ED->getTypeForDecl());
   2233   }
   2234 
   2235   SmallString<256> FullName = getUniqueTagTypeName(Ty, CGM, TheCU);
   2236 
   2237   // Create elements for each enumerator.
   2238   SmallVector<llvm::Metadata *, 16> Enumerators;
   2239   ED = ED->getDefinition();
   2240   for (const auto *Enum : ED->enumerators()) {
   2241     Enumerators.push_back(DBuilder.createEnumerator(
   2242         Enum->getName(), Enum->getInitVal().getSExtValue()));
   2243   }
   2244 
   2245   // Return a CompositeType for the enum itself.
   2246   llvm::DINodeArray EltArray = DBuilder.getOrCreateArray(Enumerators);
   2247 
   2248   llvm::DIFile *DefUnit = getOrCreateFile(ED->getLocation());
   2249   unsigned Line = getLineNumber(ED->getLocation());
   2250   llvm::DIScope *EnumContext = getDeclContextDescriptor(ED);
   2251   llvm::DIType *ClassTy =
   2252       ED->isFixed() ? getOrCreateType(ED->getIntegerType(), DefUnit) : nullptr;
   2253   return DBuilder.createEnumerationType(EnumContext, ED->getName(), DefUnit,
   2254                                         Line, Size, Align, EltArray, ClassTy,
   2255                                         FullName);
   2256 }
   2257 
   2258 static QualType UnwrapTypeForDebugInfo(QualType T, const ASTContext &C) {
   2259   Qualifiers Quals;
   2260   do {
   2261     Qualifiers InnerQuals = T.getLocalQualifiers();
   2262     // Qualifiers::operator+() doesn't like it if you add a Qualifier
   2263     // that is already there.
   2264     Quals += Qualifiers::removeCommonQualifiers(Quals, InnerQuals);
   2265     Quals += InnerQuals;
   2266     QualType LastT = T;
   2267     switch (T->getTypeClass()) {
   2268     default:
   2269       return C.getQualifiedType(T.getTypePtr(), Quals);
   2270     case Type::TemplateSpecialization: {
   2271       const auto *Spec = cast<TemplateSpecializationType>(T);
   2272       if (Spec->isTypeAlias())
   2273         return C.getQualifiedType(T.getTypePtr(), Quals);
   2274       T = Spec->desugar();
   2275       break;
   2276     }
   2277     case Type::TypeOfExpr:
   2278       T = cast<TypeOfExprType>(T)->getUnderlyingExpr()->getType();
   2279       break;
   2280     case Type::TypeOf:
   2281       T = cast<TypeOfType>(T)->getUnderlyingType();
   2282       break;
   2283     case Type::Decltype:
   2284       T = cast<DecltypeType>(T)->getUnderlyingType();
   2285       break;
   2286     case Type::UnaryTransform:
   2287       T = cast<UnaryTransformType>(T)->getUnderlyingType();
   2288       break;
   2289     case Type::Attributed:
   2290       T = cast<AttributedType>(T)->getEquivalentType();
   2291       break;
   2292     case Type::Elaborated:
   2293       T = cast<ElaboratedType>(T)->getNamedType();
   2294       break;
   2295     case Type::Paren:
   2296       T = cast<ParenType>(T)->getInnerType();
   2297       break;
   2298     case Type::SubstTemplateTypeParm:
   2299       T = cast<SubstTemplateTypeParmType>(T)->getReplacementType();
   2300       break;
   2301     case Type::Auto:
   2302       QualType DT = cast<AutoType>(T)->getDeducedType();
   2303       assert(!DT.isNull() && "Undeduced types shouldn't reach here.");
   2304       T = DT;
   2305       break;
   2306     }
   2307 
   2308     assert(T != LastT && "Type unwrapping failed to unwrap!");
   2309     (void)LastT;
   2310   } while (true);
   2311 }
   2312 
   2313 llvm::DIType *CGDebugInfo::getTypeOrNull(QualType Ty) {
   2314 
   2315   // Unwrap the type as needed for debug information.
   2316   Ty = UnwrapTypeForDebugInfo(Ty, CGM.getContext());
   2317 
   2318   auto it = TypeCache.find(Ty.getAsOpaquePtr());
   2319   if (it != TypeCache.end()) {
   2320     // Verify that the debug info still exists.
   2321     if (llvm::Metadata *V = it->second)
   2322       return cast<llvm::DIType>(V);
   2323   }
   2324 
   2325   return nullptr;
   2326 }
   2327 
   2328 void CGDebugInfo::completeTemplateDefinition(
   2329     const ClassTemplateSpecializationDecl &SD) {
   2330   if (DebugKind <= codegenoptions::DebugLineTablesOnly)
   2331     return;
   2332 
   2333   completeClassData(&SD);
   2334   // In case this type has no member function definitions being emitted, ensure
   2335   // it is retained
   2336   RetainedTypes.push_back(CGM.getContext().getRecordType(&SD).getAsOpaquePtr());
   2337 }
   2338 
   2339 llvm::DIType *CGDebugInfo::getOrCreateType(QualType Ty, llvm::DIFile *Unit) {
   2340   if (Ty.isNull())
   2341     return nullptr;
   2342 
   2343   // Unwrap the type as needed for debug information.
   2344   Ty = UnwrapTypeForDebugInfo(Ty, CGM.getContext());
   2345 
   2346   if (auto *T = getTypeOrNull(Ty))
   2347     return T;
   2348 
   2349   llvm::DIType *Res = CreateTypeNode(Ty, Unit);
   2350   void* TyPtr = Ty.getAsOpaquePtr();
   2351 
   2352   // And update the type cache.
   2353   TypeCache[TyPtr].reset(Res);
   2354 
   2355   return Res;
   2356 }
   2357 
   2358 llvm::DIModule *CGDebugInfo::getParentModuleOrNull(const Decl *D) {
   2359   // A forward declaration inside a module header does not belong to the module.
   2360   if (isa<RecordDecl>(D) && !cast<RecordDecl>(D)->getDefinition())
   2361     return nullptr;
   2362   if (DebugTypeExtRefs && D->isFromASTFile()) {
   2363     // Record a reference to an imported clang module or precompiled header.
   2364     auto *Reader = CGM.getContext().getExternalSource();
   2365     auto Idx = D->getOwningModuleID();
   2366     auto Info = Reader->getSourceDescriptor(Idx);
   2367     if (Info)
   2368       return getOrCreateModuleRef(*Info, /*SkeletonCU=*/true);
   2369   } else if (ClangModuleMap) {
   2370     // We are building a clang module or a precompiled header.
   2371     //
   2372     // TODO: When D is a CXXRecordDecl or a C++ Enum, the ODR applies
   2373     // and it wouldn't be necessary to specify the parent scope
   2374     // because the type is already unique by definition (it would look
   2375     // like the output of -fno-standalone-debug). On the other hand,
   2376     // the parent scope helps a consumer to quickly locate the object
   2377     // file where the type's definition is located, so it might be
   2378     // best to make this behavior a command line or debugger tuning
   2379     // option.
   2380     FullSourceLoc Loc(D->getLocation(), CGM.getContext().getSourceManager());
   2381     if (Module *M = ClangModuleMap->inferModuleFromLocation(Loc)) {
   2382       // This is a (sub-)module.
   2383       auto Info = ExternalASTSource::ASTSourceDescriptor(*M);
   2384       return getOrCreateModuleRef(Info, /*SkeletonCU=*/false);
   2385     } else {
   2386       // This the precompiled header being built.
   2387       return getOrCreateModuleRef(PCHDescriptor, /*SkeletonCU=*/false);
   2388     }
   2389   }
   2390 
   2391   return nullptr;
   2392 }
   2393 
   2394 llvm::DIType *CGDebugInfo::CreateTypeNode(QualType Ty, llvm::DIFile *Unit) {
   2395   // Handle qualifiers, which recursively handles what they refer to.
   2396   if (Ty.hasLocalQualifiers())
   2397     return CreateQualifiedType(Ty, Unit);
   2398 
   2399   // Work out details of type.
   2400   switch (Ty->getTypeClass()) {
   2401 #define TYPE(Class, Base)
   2402 #define ABSTRACT_TYPE(Class, Base)
   2403 #define NON_CANONICAL_TYPE(Class, Base)
   2404 #define DEPENDENT_TYPE(Class, Base) case Type::Class:
   2405 #include "clang/AST/TypeNodes.def"
   2406     llvm_unreachable("Dependent types cannot show up in debug information");
   2407 
   2408   case Type::ExtVector:
   2409   case Type::Vector:
   2410     return CreateType(cast<VectorType>(Ty), Unit);
   2411   case Type::ObjCObjectPointer:
   2412     return CreateType(cast<ObjCObjectPointerType>(Ty), Unit);
   2413   case Type::ObjCObject:
   2414     return CreateType(cast<ObjCObjectType>(Ty), Unit);
   2415   case Type::ObjCInterface:
   2416     return CreateType(cast<ObjCInterfaceType>(Ty), Unit);
   2417   case Type::Builtin:
   2418     return CreateType(cast<BuiltinType>(Ty));
   2419   case Type::Complex:
   2420     return CreateType(cast<ComplexType>(Ty));
   2421   case Type::Pointer:
   2422     return CreateType(cast<PointerType>(Ty), Unit);
   2423   case Type::Adjusted:
   2424   case Type::Decayed:
   2425     // Decayed and adjusted types use the adjusted type in LLVM and DWARF.
   2426     return CreateType(
   2427         cast<PointerType>(cast<AdjustedType>(Ty)->getAdjustedType()), Unit);
   2428   case Type::BlockPointer:
   2429     return CreateType(cast<BlockPointerType>(Ty), Unit);
   2430   case Type::Typedef:
   2431     return CreateType(cast<TypedefType>(Ty), Unit);
   2432   case Type::Record:
   2433     return CreateType(cast<RecordType>(Ty));
   2434   case Type::Enum:
   2435     return CreateEnumType(cast<EnumType>(Ty));
   2436   case Type::FunctionProto:
   2437   case Type::FunctionNoProto:
   2438     return CreateType(cast<FunctionType>(Ty), Unit);
   2439   case Type::ConstantArray:
   2440   case Type::VariableArray:
   2441   case Type::IncompleteArray:
   2442     return CreateType(cast<ArrayType>(Ty), Unit);
   2443 
   2444   case Type::LValueReference:
   2445     return CreateType(cast<LValueReferenceType>(Ty), Unit);
   2446   case Type::RValueReference:
   2447     return CreateType(cast<RValueReferenceType>(Ty), Unit);
   2448 
   2449   case Type::MemberPointer:
   2450     return CreateType(cast<MemberPointerType>(Ty), Unit);
   2451 
   2452   case Type::Atomic:
   2453     return CreateType(cast<AtomicType>(Ty), Unit);
   2454 
   2455   case Type::Pipe:
   2456     return CreateType(cast<PipeType>(Ty), Unit);
   2457 
   2458   case Type::TemplateSpecialization:
   2459     return CreateType(cast<TemplateSpecializationType>(Ty), Unit);
   2460 
   2461   case Type::Auto:
   2462   case Type::Attributed:
   2463   case Type::Elaborated:
   2464   case Type::Paren:
   2465   case Type::SubstTemplateTypeParm:
   2466   case Type::TypeOfExpr:
   2467   case Type::TypeOf:
   2468   case Type::Decltype:
   2469   case Type::UnaryTransform:
   2470   case Type::PackExpansion:
   2471     break;
   2472   }
   2473 
   2474   llvm_unreachable("type should have been unwrapped!");
   2475 }
   2476 
   2477 llvm::DICompositeType *CGDebugInfo::getOrCreateLimitedType(const RecordType *Ty,
   2478                                                            llvm::DIFile *Unit) {
   2479   QualType QTy(Ty, 0);
   2480 
   2481   auto *T = cast_or_null<llvm::DICompositeType>(getTypeOrNull(QTy));
   2482 
   2483   // We may have cached a forward decl when we could have created
   2484   // a non-forward decl. Go ahead and create a non-forward decl
   2485   // now.
   2486   if (T && !T->isForwardDecl())
   2487     return T;
   2488 
   2489   // Otherwise create the type.
   2490   llvm::DICompositeType *Res = CreateLimitedType(Ty);
   2491 
   2492   // Propagate members from the declaration to the definition
   2493   // CreateType(const RecordType*) will overwrite this with the members in the
   2494   // correct order if the full type is needed.
   2495   DBuilder.replaceArrays(Res, T ? T->getElements() : llvm::DINodeArray());
   2496 
   2497   // And update the type cache.
   2498   TypeCache[QTy.getAsOpaquePtr()].reset(Res);
   2499   return Res;
   2500 }
   2501 
   2502 // TODO: Currently used for context chains when limiting debug info.
   2503 llvm::DICompositeType *CGDebugInfo::CreateLimitedType(const RecordType *Ty) {
   2504   RecordDecl *RD = Ty->getDecl();
   2505 
   2506   // Get overall information about the record type for the debug info.
   2507   llvm::DIFile *DefUnit = getOrCreateFile(RD->getLocation());
   2508   unsigned Line = getLineNumber(RD->getLocation());
   2509   StringRef RDName = getClassName(RD);
   2510 
   2511   llvm::DIScope *RDContext = getDeclContextDescriptor(RD);
   2512 
   2513   // If we ended up creating the type during the context chain construction,
   2514   // just return that.
   2515   auto *T = cast_or_null<llvm::DICompositeType>(
   2516       getTypeOrNull(CGM.getContext().getRecordType(RD)));
   2517   if (T && (!T->isForwardDecl() || !RD->getDefinition()))
   2518     return T;
   2519 
   2520   // If this is just a forward or incomplete declaration, construct an
   2521   // appropriately marked node and just return it.
   2522   const RecordDecl *D = RD->getDefinition();
   2523   if (!D || !D->isCompleteDefinition())
   2524     return getOrCreateRecordFwdDecl(Ty, RDContext);
   2525 
   2526   uint64_t Size = CGM.getContext().getTypeSize(Ty);
   2527   uint64_t Align = CGM.getContext().getTypeAlign(Ty);
   2528 
   2529   SmallString<256> FullName = getUniqueTagTypeName(Ty, CGM, TheCU);
   2530 
   2531   llvm::DICompositeType *RealDecl = DBuilder.createReplaceableCompositeType(
   2532       getTagForRecord(RD), RDName, RDContext, DefUnit, Line, 0, Size, Align, 0,
   2533       FullName);
   2534 
   2535   // Elements of composite types usually have back to the type, creating
   2536   // uniquing cycles.  Distinct nodes are more efficient.
   2537   switch (RealDecl->getTag()) {
   2538   default:
   2539     llvm_unreachable("invalid composite type tag");
   2540 
   2541   case llvm::dwarf::DW_TAG_array_type:
   2542   case llvm::dwarf::DW_TAG_enumeration_type:
   2543     // Array elements and most enumeration elements don't have back references,
   2544     // so they don't tend to be involved in uniquing cycles and there is some
   2545     // chance of merging them when linking together two modules.  Only make
   2546     // them distinct if they are ODR-uniqued.
   2547     if (FullName.empty())
   2548       break;
   2549 
   2550   case llvm::dwarf::DW_TAG_structure_type:
   2551   case llvm::dwarf::DW_TAG_union_type:
   2552   case llvm::dwarf::DW_TAG_class_type:
   2553     // Immediatley resolve to a distinct node.
   2554     RealDecl =
   2555         llvm::MDNode::replaceWithDistinct(llvm::TempDICompositeType(RealDecl));
   2556     break;
   2557   }
   2558 
   2559   RegionMap[Ty->getDecl()].reset(RealDecl);
   2560   TypeCache[QualType(Ty, 0).getAsOpaquePtr()].reset(RealDecl);
   2561 
   2562   if (const ClassTemplateSpecializationDecl *TSpecial =
   2563           dyn_cast<ClassTemplateSpecializationDecl>(RD))
   2564     DBuilder.replaceArrays(RealDecl, llvm::DINodeArray(),
   2565                            CollectCXXTemplateParams(TSpecial, DefUnit));
   2566   return RealDecl;
   2567 }
   2568 
   2569 void CGDebugInfo::CollectContainingType(const CXXRecordDecl *RD,
   2570                                         llvm::DICompositeType *RealDecl) {
   2571   // A class's primary base or the class itself contains the vtable.
   2572   llvm::DICompositeType *ContainingType = nullptr;
   2573   const ASTRecordLayout &RL = CGM.getContext().getASTRecordLayout(RD);
   2574   if (const CXXRecordDecl *PBase = RL.getPrimaryBase()) {
   2575     // Seek non-virtual primary base root.
   2576     while (1) {
   2577       const ASTRecordLayout &BRL = CGM.getContext().getASTRecordLayout(PBase);
   2578       const CXXRecordDecl *PBT = BRL.getPrimaryBase();
   2579       if (PBT && !BRL.isPrimaryBaseVirtual())
   2580         PBase = PBT;
   2581       else
   2582         break;
   2583     }
   2584     ContainingType = cast<llvm::DICompositeType>(
   2585         getOrCreateType(QualType(PBase->getTypeForDecl(), 0),
   2586                         getOrCreateFile(RD->getLocation())));
   2587   } else if (RD->isDynamicClass())
   2588     ContainingType = RealDecl;
   2589 
   2590   DBuilder.replaceVTableHolder(RealDecl, ContainingType);
   2591 }
   2592 
   2593 llvm::DIType *CGDebugInfo::CreateMemberType(llvm::DIFile *Unit, QualType FType,
   2594                                             StringRef Name, uint64_t *Offset) {
   2595   llvm::DIType *FieldTy = CGDebugInfo::getOrCreateType(FType, Unit);
   2596   uint64_t FieldSize = CGM.getContext().getTypeSize(FType);
   2597   unsigned FieldAlign = CGM.getContext().getTypeAlign(FType);
   2598   llvm::DIType *Ty = DBuilder.createMemberType(Unit, Name, Unit, 0, FieldSize,
   2599                                                FieldAlign, *Offset, 0, FieldTy);
   2600   *Offset += FieldSize;
   2601   return Ty;
   2602 }
   2603 
   2604 void CGDebugInfo::collectFunctionDeclProps(GlobalDecl GD, llvm::DIFile *Unit,
   2605                                            StringRef &Name,
   2606                                            StringRef &LinkageName,
   2607                                            llvm::DIScope *&FDContext,
   2608                                            llvm::DINodeArray &TParamsArray,
   2609                                            unsigned &Flags) {
   2610   const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
   2611   Name = getFunctionName(FD);
   2612   // Use mangled name as linkage name for C/C++ functions.
   2613   if (FD->hasPrototype()) {
   2614     LinkageName = CGM.getMangledName(GD);
   2615     Flags |= llvm::DINode::FlagPrototyped;
   2616   }
   2617   // No need to replicate the linkage name if it isn't different from the
   2618   // subprogram name, no need to have it at all unless coverage is enabled or
   2619   // debug is set to more than just line tables.
   2620   if (LinkageName == Name || (!CGM.getCodeGenOpts().EmitGcovArcs &&
   2621                               !CGM.getCodeGenOpts().EmitGcovNotes &&
   2622                               DebugKind <= codegenoptions::DebugLineTablesOnly))
   2623     LinkageName = StringRef();
   2624 
   2625   if (DebugKind >= codegenoptions::LimitedDebugInfo) {
   2626     if (const NamespaceDecl *NSDecl =
   2627         dyn_cast_or_null<NamespaceDecl>(FD->getDeclContext()))
   2628       FDContext = getOrCreateNameSpace(NSDecl);
   2629     else if (const RecordDecl *RDecl =
   2630              dyn_cast_or_null<RecordDecl>(FD->getDeclContext())) {
   2631       llvm::DIScope *Mod = getParentModuleOrNull(RDecl);
   2632       FDContext = getContextDescriptor(RDecl, Mod ? Mod : TheCU);
   2633     }
   2634     // Collect template parameters.
   2635     TParamsArray = CollectFunctionTemplateParams(FD, Unit);
   2636   }
   2637 }
   2638 
   2639 void CGDebugInfo::collectVarDeclProps(const VarDecl *VD, llvm::DIFile *&Unit,
   2640                                       unsigned &LineNo, QualType &T,
   2641                                       StringRef &Name, StringRef &LinkageName,
   2642                                       llvm::DIScope *&VDContext) {
   2643   Unit = getOrCreateFile(VD->getLocation());
   2644   LineNo = getLineNumber(VD->getLocation());
   2645 
   2646   setLocation(VD->getLocation());
   2647 
   2648   T = VD->getType();
   2649   if (T->isIncompleteArrayType()) {
   2650     // CodeGen turns int[] into int[1] so we'll do the same here.
   2651     llvm::APInt ConstVal(32, 1);
   2652     QualType ET = CGM.getContext().getAsArrayType(T)->getElementType();
   2653 
   2654     T = CGM.getContext().getConstantArrayType(ET, ConstVal,
   2655                                               ArrayType::Normal, 0);
   2656   }
   2657 
   2658   Name = VD->getName();
   2659   if (VD->getDeclContext() && !isa<FunctionDecl>(VD->getDeclContext()) &&
   2660       !isa<ObjCMethodDecl>(VD->getDeclContext()))
   2661     LinkageName = CGM.getMangledName(VD);
   2662   if (LinkageName == Name)
   2663     LinkageName = StringRef();
   2664 
   2665   // Since we emit declarations (DW_AT_members) for static members, place the
   2666   // definition of those static members in the namespace they were declared in
   2667   // in the source code (the lexical decl context).
   2668   // FIXME: Generalize this for even non-member global variables where the
   2669   // declaration and definition may have different lexical decl contexts, once
   2670   // we have support for emitting declarations of (non-member) global variables.
   2671   const DeclContext *DC = VD->isStaticDataMember() ? VD->getLexicalDeclContext()
   2672                                                    : VD->getDeclContext();
   2673   // When a record type contains an in-line initialization of a static data
   2674   // member, and the record type is marked as __declspec(dllexport), an implicit
   2675   // definition of the member will be created in the record context.  DWARF
   2676   // doesn't seem to have a nice way to describe this in a form that consumers
   2677   // are likely to understand, so fake the "normal" situation of a definition
   2678   // outside the class by putting it in the global scope.
   2679   if (DC->isRecord())
   2680     DC = CGM.getContext().getTranslationUnitDecl();
   2681 
   2682  llvm::DIScope *Mod = getParentModuleOrNull(VD);
   2683  VDContext = getContextDescriptor(cast<Decl>(DC), Mod ? Mod : TheCU);
   2684 }
   2685 
   2686 llvm::DISubprogram *
   2687 CGDebugInfo::getFunctionForwardDeclaration(const FunctionDecl *FD) {
   2688   llvm::DINodeArray TParamsArray;
   2689   StringRef Name, LinkageName;
   2690   unsigned Flags = 0;
   2691   SourceLocation Loc = FD->getLocation();
   2692   llvm::DIFile *Unit = getOrCreateFile(Loc);
   2693   llvm::DIScope *DContext = Unit;
   2694   unsigned Line = getLineNumber(Loc);
   2695 
   2696   collectFunctionDeclProps(FD, Unit, Name, LinkageName, DContext,
   2697                            TParamsArray, Flags);
   2698   // Build function type.
   2699   SmallVector<QualType, 16> ArgTypes;
   2700   for (const ParmVarDecl *Parm: FD->parameters())
   2701     ArgTypes.push_back(Parm->getType());
   2702   CallingConv CC = FD->getType()->castAs<FunctionType>()->getCallConv();
   2703   QualType FnType = CGM.getContext().getFunctionType(
   2704       FD->getReturnType(), ArgTypes, FunctionProtoType::ExtProtoInfo(CC));
   2705   llvm::DISubprogram *SP = DBuilder.createTempFunctionFwdDecl(
   2706       DContext, Name, LinkageName, Unit, Line,
   2707       getOrCreateFunctionType(FD, FnType, Unit), !FD->isExternallyVisible(),
   2708       /* isDefinition = */ false, 0, Flags, CGM.getLangOpts().Optimize,
   2709       TParamsArray.get(), getFunctionDeclaration(FD));
   2710   const FunctionDecl *CanonDecl = cast<FunctionDecl>(FD->getCanonicalDecl());
   2711   FwdDeclReplaceMap.emplace_back(std::piecewise_construct,
   2712                                  std::make_tuple(CanonDecl),
   2713                                  std::make_tuple(SP));
   2714   return SP;
   2715 }
   2716 
   2717 llvm::DIGlobalVariable *
   2718 CGDebugInfo::getGlobalVariableForwardDeclaration(const VarDecl *VD) {
   2719   QualType T;
   2720   StringRef Name, LinkageName;
   2721   SourceLocation Loc = VD->getLocation();
   2722   llvm::DIFile *Unit = getOrCreateFile(Loc);
   2723   llvm::DIScope *DContext = Unit;
   2724   unsigned Line = getLineNumber(Loc);
   2725 
   2726   collectVarDeclProps(VD, Unit, Line, T, Name, LinkageName, DContext);
   2727   auto *GV = DBuilder.createTempGlobalVariableFwdDecl(
   2728       DContext, Name, LinkageName, Unit, Line, getOrCreateType(T, Unit),
   2729       !VD->isExternallyVisible(), nullptr, nullptr);
   2730   FwdDeclReplaceMap.emplace_back(
   2731       std::piecewise_construct,
   2732       std::make_tuple(cast<VarDecl>(VD->getCanonicalDecl())),
   2733       std::make_tuple(static_cast<llvm::Metadata *>(GV)));
   2734   return GV;
   2735 }
   2736 
   2737 llvm::DINode *CGDebugInfo::getDeclarationOrDefinition(const Decl *D) {
   2738   // We only need a declaration (not a definition) of the type - so use whatever
   2739   // we would otherwise do to get a type for a pointee. (forward declarations in
   2740   // limited debug info, full definitions (if the type definition is available)
   2741   // in unlimited debug info)
   2742   if (const TypeDecl *TD = dyn_cast<TypeDecl>(D))
   2743     return getOrCreateType(CGM.getContext().getTypeDeclType(TD),
   2744                            getOrCreateFile(TD->getLocation()));
   2745   auto I = DeclCache.find(D->getCanonicalDecl());
   2746 
   2747   if (I != DeclCache.end())
   2748     return dyn_cast_or_null<llvm::DINode>(I->second);
   2749 
   2750   // No definition for now. Emit a forward definition that might be
   2751   // merged with a potential upcoming definition.
   2752   if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
   2753     return getFunctionForwardDeclaration(FD);
   2754   else if (const auto *VD = dyn_cast<VarDecl>(D))
   2755     return getGlobalVariableForwardDeclaration(VD);
   2756 
   2757   return nullptr;
   2758 }
   2759 
   2760 llvm::DISubprogram *CGDebugInfo::getFunctionDeclaration(const Decl *D) {
   2761   if (!D || DebugKind <= codegenoptions::DebugLineTablesOnly)
   2762     return nullptr;
   2763 
   2764   const FunctionDecl *FD = dyn_cast<FunctionDecl>(D);
   2765   if (!FD)
   2766     return nullptr;
   2767 
   2768   // Setup context.
   2769   auto *S = getDeclContextDescriptor(D);
   2770 
   2771   auto MI = SPCache.find(FD->getCanonicalDecl());
   2772   if (MI == SPCache.end()) {
   2773     if (const CXXMethodDecl *MD =
   2774             dyn_cast<CXXMethodDecl>(FD->getCanonicalDecl())) {
   2775       return CreateCXXMemberFunction(MD, getOrCreateFile(MD->getLocation()),
   2776                                      cast<llvm::DICompositeType>(S));
   2777     }
   2778   }
   2779   if (MI != SPCache.end()) {
   2780     auto *SP = dyn_cast_or_null<llvm::DISubprogram>(MI->second);
   2781     if (SP && !SP->isDefinition())
   2782       return SP;
   2783   }
   2784 
   2785   for (auto NextFD : FD->redecls()) {
   2786     auto MI = SPCache.find(NextFD->getCanonicalDecl());
   2787     if (MI != SPCache.end()) {
   2788       auto *SP = dyn_cast_or_null<llvm::DISubprogram>(MI->second);
   2789       if (SP && !SP->isDefinition())
   2790         return SP;
   2791     }
   2792   }
   2793   return nullptr;
   2794 }
   2795 
   2796 // getOrCreateFunctionType - Construct type. If it is a c++ method, include
   2797 // implicit parameter "this".
   2798 llvm::DISubroutineType *CGDebugInfo::getOrCreateFunctionType(const Decl *D,
   2799                                                              QualType FnType,
   2800                                                              llvm::DIFile *F) {
   2801   if (!D || DebugKind <= codegenoptions::DebugLineTablesOnly)
   2802     // Create fake but valid subroutine type. Otherwise -verify would fail, and
   2803     // subprogram DIE will miss DW_AT_decl_file and DW_AT_decl_line fields.
   2804     return DBuilder.createSubroutineType(DBuilder.getOrCreateTypeArray(None));
   2805 
   2806   if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D))
   2807     return getOrCreateMethodType(Method, F);
   2808 
   2809   const auto *FTy = FnType->getAs<FunctionType>();
   2810   CallingConv CC = FTy ? FTy->getCallConv() : CallingConv::CC_C;
   2811 
   2812   if (const ObjCMethodDecl *OMethod = dyn_cast<ObjCMethodDecl>(D)) {
   2813     // Add "self" and "_cmd"
   2814     SmallVector<llvm::Metadata *, 16> Elts;
   2815 
   2816     // First element is always return type. For 'void' functions it is NULL.
   2817     QualType ResultTy = OMethod->getReturnType();
   2818 
   2819     // Replace the instancetype keyword with the actual type.
   2820     if (ResultTy == CGM.getContext().getObjCInstanceType())
   2821       ResultTy = CGM.getContext().getPointerType(
   2822           QualType(OMethod->getClassInterface()->getTypeForDecl(), 0));
   2823 
   2824     Elts.push_back(getOrCreateType(ResultTy, F));
   2825     // "self" pointer is always first argument.
   2826     QualType SelfDeclTy;
   2827     if (auto *SelfDecl = OMethod->getSelfDecl())
   2828       SelfDeclTy = SelfDecl->getType();
   2829     else if (auto *FPT = dyn_cast<FunctionProtoType>(FnType))
   2830       if (FPT->getNumParams() > 1)
   2831         SelfDeclTy = FPT->getParamType(0);
   2832     if (!SelfDeclTy.isNull())
   2833       Elts.push_back(CreateSelfType(SelfDeclTy, getOrCreateType(SelfDeclTy, F)));
   2834     // "_cmd" pointer is always second argument.
   2835     Elts.push_back(DBuilder.createArtificialType(
   2836         getOrCreateType(CGM.getContext().getObjCSelType(), F)));
   2837     // Get rest of the arguments.
   2838     for (const auto *PI : OMethod->parameters())
   2839       Elts.push_back(getOrCreateType(PI->getType(), F));
   2840     // Variadic methods need a special marker at the end of the type list.
   2841     if (OMethod->isVariadic())
   2842       Elts.push_back(DBuilder.createUnspecifiedParameter());
   2843 
   2844     llvm::DITypeRefArray EltTypeArray = DBuilder.getOrCreateTypeArray(Elts);
   2845     return DBuilder.createSubroutineType(EltTypeArray, 0, getDwarfCC(CC));
   2846   }
   2847 
   2848   // Handle variadic function types; they need an additional
   2849   // unspecified parameter.
   2850   if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
   2851     if (FD->isVariadic()) {
   2852       SmallVector<llvm::Metadata *, 16> EltTys;
   2853       EltTys.push_back(getOrCreateType(FD->getReturnType(), F));
   2854       if (const FunctionProtoType *FPT = dyn_cast<FunctionProtoType>(FnType))
   2855         for (unsigned i = 0, e = FPT->getNumParams(); i != e; ++i)
   2856           EltTys.push_back(getOrCreateType(FPT->getParamType(i), F));
   2857       EltTys.push_back(DBuilder.createUnspecifiedParameter());
   2858       llvm::DITypeRefArray EltTypeArray = DBuilder.getOrCreateTypeArray(EltTys);
   2859       return DBuilder.createSubroutineType(EltTypeArray, 0, getDwarfCC(CC));
   2860     }
   2861 
   2862   return cast<llvm::DISubroutineType>(getOrCreateType(FnType, F));
   2863 }
   2864 
   2865 void CGDebugInfo::EmitFunctionStart(GlobalDecl GD, SourceLocation Loc,
   2866                                     SourceLocation ScopeLoc, QualType FnType,
   2867                                     llvm::Function *Fn, CGBuilderTy &Builder) {
   2868 
   2869   StringRef Name;
   2870   StringRef LinkageName;
   2871 
   2872   FnBeginRegionCount.push_back(LexicalBlockStack.size());
   2873 
   2874   const Decl *D = GD.getDecl();
   2875   bool HasDecl = (D != nullptr);
   2876 
   2877   unsigned Flags = 0;
   2878   llvm::DIFile *Unit = getOrCreateFile(Loc);
   2879   llvm::DIScope *FDContext = Unit;
   2880   llvm::DINodeArray TParamsArray;
   2881   if (!HasDecl) {
   2882     // Use llvm function name.
   2883     LinkageName = Fn->getName();
   2884   } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
   2885     // If there is a subprogram for this function available then use it.
   2886     auto FI = SPCache.find(FD->getCanonicalDecl());
   2887     if (FI != SPCache.end()) {
   2888       auto *SP = dyn_cast_or_null<llvm::DISubprogram>(FI->second);
   2889       if (SP && SP->isDefinition()) {
   2890         LexicalBlockStack.emplace_back(SP);
   2891         RegionMap[D].reset(SP);
   2892         return;
   2893       }
   2894     }
   2895     collectFunctionDeclProps(GD, Unit, Name, LinkageName, FDContext,
   2896                              TParamsArray, Flags);
   2897   } else if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(D)) {
   2898     Name = getObjCMethodName(OMD);
   2899     Flags |= llvm::DINode::FlagPrototyped;
   2900   } else {
   2901     // Use llvm function name.
   2902     Name = Fn->getName();
   2903     Flags |= llvm::DINode::FlagPrototyped;
   2904   }
   2905   if (!Name.empty() && Name[0] == '\01')
   2906     Name = Name.substr(1);
   2907 
   2908   if (!HasDecl || D->isImplicit()) {
   2909     Flags |= llvm::DINode::FlagArtificial;
   2910     // Artificial functions without a location should not silently reuse CurLoc.
   2911     if (Loc.isInvalid())
   2912       CurLoc = SourceLocation();
   2913   }
   2914   unsigned LineNo = getLineNumber(Loc);
   2915   unsigned ScopeLine = getLineNumber(ScopeLoc);
   2916 
   2917   // FIXME: The function declaration we're constructing here is mostly reusing
   2918   // declarations from CXXMethodDecl and not constructing new ones for arbitrary
   2919   // FunctionDecls. When/if we fix this we can have FDContext be TheCU/null for
   2920   // all subprograms instead of the actual context since subprogram definitions
   2921   // are emitted as CU level entities by the backend.
   2922   llvm::DISubprogram *SP = DBuilder.createFunction(
   2923       FDContext, Name, LinkageName, Unit, LineNo,
   2924       getOrCreateFunctionType(D, FnType, Unit), Fn->hasLocalLinkage(),
   2925       true /*definition*/, ScopeLine, Flags, CGM.getLangOpts().Optimize,
   2926       TParamsArray.get(), getFunctionDeclaration(D));
   2927   Fn->setSubprogram(SP);
   2928   // We might get here with a VarDecl in the case we're generating
   2929   // code for the initialization of globals. Do not record these decls
   2930   // as they will overwrite the actual VarDecl Decl in the cache.
   2931   if (HasDecl && isa<FunctionDecl>(D))
   2932     DeclCache[D->getCanonicalDecl()].reset(static_cast<llvm::Metadata *>(SP));
   2933 
   2934   // Push the function onto the lexical block stack.
   2935   LexicalBlockStack.emplace_back(SP);
   2936 
   2937   if (HasDecl)
   2938     RegionMap[D].reset(SP);
   2939 }
   2940 
   2941 void CGDebugInfo::EmitFunctionDecl(GlobalDecl GD, SourceLocation Loc,
   2942                                    QualType FnType) {
   2943   StringRef Name;
   2944   StringRef LinkageName;
   2945 
   2946   const Decl *D = GD.getDecl();
   2947   if (!D)
   2948     return;
   2949 
   2950   unsigned Flags = 0;
   2951   llvm::DIFile *Unit = getOrCreateFile(Loc);
   2952   llvm::DIScope *FDContext = getDeclContextDescriptor(D);
   2953   llvm::DINodeArray TParamsArray;
   2954   if (isa<FunctionDecl>(D)) {
   2955     // If there is a DISubprogram for this function available then use it.
   2956     collectFunctionDeclProps(GD, Unit, Name, LinkageName, FDContext,
   2957                              TParamsArray, Flags);
   2958   } else if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(D)) {
   2959     Name = getObjCMethodName(OMD);
   2960     Flags |= llvm::DINode::FlagPrototyped;
   2961   } else {
   2962     llvm_unreachable("not a function or ObjC method");
   2963   }
   2964   if (!Name.empty() && Name[0] == '\01')
   2965     Name = Name.substr(1);
   2966 
   2967   if (D->isImplicit()) {
   2968     Flags |= llvm::DINode::FlagArtificial;
   2969     // Artificial functions without a location should not silently reuse CurLoc.
   2970     if (Loc.isInvalid())
   2971       CurLoc = SourceLocation();
   2972   }
   2973   unsigned LineNo = getLineNumber(Loc);
   2974   unsigned ScopeLine = 0;
   2975 
   2976   DBuilder.retainType(DBuilder.createFunction(
   2977       FDContext, Name, LinkageName, Unit, LineNo,
   2978       getOrCreateFunctionType(D, FnType, Unit), false /*internalLinkage*/,
   2979       false /*definition*/, ScopeLine, Flags, CGM.getLangOpts().Optimize,
   2980       TParamsArray.get(), getFunctionDeclaration(D)));
   2981 }
   2982 
   2983 void CGDebugInfo::EmitLocation(CGBuilderTy &Builder, SourceLocation Loc) {
   2984   // Update our current location
   2985   setLocation(Loc);
   2986 
   2987   if (CurLoc.isInvalid() || CurLoc.isMacroID())
   2988     return;
   2989 
   2990   llvm::MDNode *Scope = LexicalBlockStack.back();
   2991   Builder.SetCurrentDebugLocation(llvm::DebugLoc::get(
   2992       getLineNumber(CurLoc), getColumnNumber(CurLoc), Scope));
   2993 }
   2994 
   2995 void CGDebugInfo::CreateLexicalBlock(SourceLocation Loc) {
   2996   llvm::MDNode *Back = nullptr;
   2997   if (!LexicalBlockStack.empty())
   2998     Back = LexicalBlockStack.back().get();
   2999   LexicalBlockStack.emplace_back(DBuilder.createLexicalBlock(
   3000       cast<llvm::DIScope>(Back), getOrCreateFile(CurLoc), getLineNumber(CurLoc),
   3001       getColumnNumber(CurLoc)));
   3002 }
   3003 
   3004 void CGDebugInfo::EmitLexicalBlockStart(CGBuilderTy &Builder,
   3005                                         SourceLocation Loc) {
   3006   // Set our current location.
   3007   setLocation(Loc);
   3008 
   3009   // Emit a line table change for the current location inside the new scope.
   3010   Builder.SetCurrentDebugLocation(llvm::DebugLoc::get(
   3011       getLineNumber(Loc), getColumnNumber(Loc), LexicalBlockStack.back()));
   3012 
   3013   if (DebugKind <= codegenoptions::DebugLineTablesOnly)
   3014     return;
   3015 
   3016   // Create a new lexical block and push it on the stack.
   3017   CreateLexicalBlock(Loc);
   3018 }
   3019 
   3020 void CGDebugInfo::EmitLexicalBlockEnd(CGBuilderTy &Builder,
   3021                                       SourceLocation Loc) {
   3022   assert(!LexicalBlockStack.empty() && "Region stack mismatch, stack empty!");
   3023 
   3024   // Provide an entry in the line table for the end of the block.
   3025   EmitLocation(Builder, Loc);
   3026 
   3027   if (DebugKind <= codegenoptions::DebugLineTablesOnly)
   3028     return;
   3029 
   3030   LexicalBlockStack.pop_back();
   3031 }
   3032 
   3033 void CGDebugInfo::EmitFunctionEnd(CGBuilderTy &Builder) {
   3034   assert(!LexicalBlockStack.empty() && "Region stack mismatch, stack empty!");
   3035   unsigned RCount = FnBeginRegionCount.back();
   3036   assert(RCount <= LexicalBlockStack.size() && "Region stack mismatch");
   3037 
   3038   // Pop all regions for this function.
   3039   while (LexicalBlockStack.size() != RCount) {
   3040     // Provide an entry in the line table for the end of the block.
   3041     EmitLocation(Builder, CurLoc);
   3042     LexicalBlockStack.pop_back();
   3043   }
   3044   FnBeginRegionCount.pop_back();
   3045 }
   3046 
   3047 llvm::DIType *CGDebugInfo::EmitTypeForVarWithBlocksAttr(const VarDecl *VD,
   3048                                                         uint64_t *XOffset) {
   3049 
   3050   SmallVector<llvm::Metadata *, 5> EltTys;
   3051   QualType FType;
   3052   uint64_t FieldSize, FieldOffset;
   3053   unsigned FieldAlign;
   3054 
   3055   llvm::DIFile *Unit = getOrCreateFile(VD->getLocation());
   3056   QualType Type = VD->getType();
   3057 
   3058   FieldOffset = 0;
   3059   FType = CGM.getContext().getPointerType(CGM.getContext().VoidTy);
   3060   EltTys.push_back(CreateMemberType(Unit, FType, "__isa", &FieldOffset));
   3061   EltTys.push_back(CreateMemberType(Unit, FType, "__forwarding", &FieldOffset));
   3062   FType = CGM.getContext().IntTy;
   3063   EltTys.push_back(CreateMemberType(Unit, FType, "__flags", &FieldOffset));
   3064   EltTys.push_back(CreateMemberType(Unit, FType, "__size", &FieldOffset));
   3065 
   3066   bool HasCopyAndDispose = CGM.getContext().BlockRequiresCopying(Type, VD);
   3067   if (HasCopyAndDispose) {
   3068     FType = CGM.getContext().getPointerType(CGM.getContext().VoidTy);
   3069     EltTys.push_back(
   3070         CreateMemberType(Unit, FType, "__copy_helper", &FieldOffset));
   3071     EltTys.push_back(
   3072         CreateMemberType(Unit, FType, "__destroy_helper", &FieldOffset));
   3073   }
   3074   bool HasByrefExtendedLayout;
   3075   Qualifiers::ObjCLifetime Lifetime;
   3076   if (CGM.getContext().getByrefLifetime(Type, Lifetime,
   3077                                         HasByrefExtendedLayout) &&
   3078       HasByrefExtendedLayout) {
   3079     FType = CGM.getContext().getPointerType(CGM.getContext().VoidTy);
   3080     EltTys.push_back(
   3081         CreateMemberType(Unit, FType, "__byref_variable_layout", &FieldOffset));
   3082   }
   3083 
   3084   CharUnits Align = CGM.getContext().getDeclAlign(VD);
   3085   if (Align > CGM.getContext().toCharUnitsFromBits(
   3086                   CGM.getTarget().getPointerAlign(0))) {
   3087     CharUnits FieldOffsetInBytes =
   3088         CGM.getContext().toCharUnitsFromBits(FieldOffset);
   3089     CharUnits AlignedOffsetInBytes = FieldOffsetInBytes.alignTo(Align);
   3090     CharUnits NumPaddingBytes = AlignedOffsetInBytes - FieldOffsetInBytes;
   3091 
   3092     if (NumPaddingBytes.isPositive()) {
   3093       llvm::APInt pad(32, NumPaddingBytes.getQuantity());
   3094       FType = CGM.getContext().getConstantArrayType(CGM.getContext().CharTy,
   3095                                                     pad, ArrayType::Normal, 0);
   3096       EltTys.push_back(CreateMemberType(Unit, FType, "", &FieldOffset));
   3097     }
   3098   }
   3099 
   3100   FType = Type;
   3101   llvm::DIType *FieldTy = getOrCreateType(FType, Unit);
   3102   FieldSize = CGM.getContext().getTypeSize(FType);
   3103   FieldAlign = CGM.getContext().toBits(Align);
   3104 
   3105   *XOffset = FieldOffset;
   3106   FieldTy = DBuilder.createMemberType(Unit, VD->getName(), Unit, 0, FieldSize,
   3107                                       FieldAlign, FieldOffset, 0, FieldTy);
   3108   EltTys.push_back(FieldTy);
   3109   FieldOffset += FieldSize;
   3110 
   3111   llvm::DINodeArray Elements = DBuilder.getOrCreateArray(EltTys);
   3112 
   3113   unsigned Flags = llvm::DINode::FlagBlockByrefStruct;
   3114 
   3115   return DBuilder.createStructType(Unit, "", Unit, 0, FieldOffset, 0, Flags,
   3116                                    nullptr, Elements);
   3117 }
   3118 
   3119 void CGDebugInfo::EmitDeclare(const VarDecl *VD, llvm::Value *Storage,
   3120                               llvm::Optional<unsigned> ArgNo,
   3121                               CGBuilderTy &Builder) {
   3122   assert(DebugKind >= codegenoptions::LimitedDebugInfo);
   3123   assert(!LexicalBlockStack.empty() && "Region stack mismatch, stack empty!");
   3124   if (VD->hasAttr<NoDebugAttr>())
   3125     return;
   3126 
   3127   bool Unwritten =
   3128       VD->isImplicit() || (isa<Decl>(VD->getDeclContext()) &&
   3129                            cast<Decl>(VD->getDeclContext())->isImplicit());
   3130   llvm::DIFile *Unit = nullptr;
   3131   if (!Unwritten)
   3132     Unit = getOrCreateFile(VD->getLocation());
   3133   llvm::DIType *Ty;
   3134   uint64_t XOffset = 0;
   3135   if (VD->hasAttr<BlocksAttr>())
   3136     Ty = EmitTypeForVarWithBlocksAttr(VD, &XOffset);
   3137   else
   3138     Ty = getOrCreateType(VD->getType(), Unit);
   3139 
   3140   // If there is no debug info for this type then do not emit debug info
   3141   // for this variable.
   3142   if (!Ty)
   3143     return;
   3144 
   3145   // Get location information.
   3146   unsigned Line = 0;
   3147   unsigned Column = 0;
   3148   if (!Unwritten) {
   3149     Line = getLineNumber(VD->getLocation());
   3150     Column = getColumnNumber(VD->getLocation());
   3151   }
   3152   SmallVector<int64_t, 9> Expr;
   3153   unsigned Flags = 0;
   3154   if (VD->isImplicit())
   3155     Flags |= llvm::DINode::FlagArtificial;
   3156   // If this is the first argument and it is implicit then
   3157   // give it an object pointer flag.
   3158   // FIXME: There has to be a better way to do this, but for static
   3159   // functions there won't be an implicit param at arg1 and
   3160   // otherwise it is 'self' or 'this'.
   3161   if (isa<ImplicitParamDecl>(VD) && ArgNo && *ArgNo == 1)
   3162     Flags |= llvm::DINode::FlagObjectPointer;
   3163   if (llvm::Argument *Arg = dyn_cast<llvm::Argument>(Storage))
   3164     if (Arg->getType()->isPointerTy() && !Arg->hasByValAttr() &&
   3165         !VD->getType()->isPointerType())
   3166       Expr.push_back(llvm::dwarf::DW_OP_deref);
   3167 
   3168   auto *Scope = cast<llvm::DIScope>(LexicalBlockStack.back());
   3169 
   3170   StringRef Name = VD->getName();
   3171   if (!Name.empty()) {
   3172     if (VD->hasAttr<BlocksAttr>()) {
   3173       CharUnits offset = CharUnits::fromQuantity(32);
   3174       Expr.push_back(llvm::dwarf::DW_OP_plus);
   3175       // offset of __forwarding field
   3176       offset = CGM.getContext().toCharUnitsFromBits(
   3177           CGM.getTarget().getPointerWidth(0));
   3178       Expr.push_back(offset.getQuantity());
   3179       Expr.push_back(llvm::dwarf::DW_OP_deref);
   3180       Expr.push_back(llvm::dwarf::DW_OP_plus);
   3181       // offset of x field
   3182       offset = CGM.getContext().toCharUnitsFromBits(XOffset);
   3183       Expr.push_back(offset.getQuantity());
   3184 
   3185       // Create the descriptor for the variable.
   3186       auto *D = ArgNo
   3187                     ? DBuilder.createParameterVariable(Scope, VD->getName(),
   3188                                                        *ArgNo, Unit, Line, Ty)
   3189                     : DBuilder.createAutoVariable(Scope, VD->getName(), Unit,
   3190                                                   Line, Ty);
   3191 
   3192       // Insert an llvm.dbg.declare into the current block.
   3193       DBuilder.insertDeclare(Storage, D, DBuilder.createExpression(Expr),
   3194                              llvm::DebugLoc::get(Line, Column, Scope),
   3195                              Builder.GetInsertBlock());
   3196       return;
   3197     } else if (isa<VariableArrayType>(VD->getType()))
   3198       Expr.push_back(llvm::dwarf::DW_OP_deref);
   3199   } else if (const RecordType *RT = dyn_cast<RecordType>(VD->getType())) {
   3200     // If VD is an anonymous union then Storage represents value for
   3201     // all union fields.
   3202     const RecordDecl *RD = cast<RecordDecl>(RT->getDecl());
   3203     if (RD->isUnion() && RD->isAnonymousStructOrUnion()) {
   3204       // GDB has trouble finding local variables in anonymous unions, so we emit
   3205       // artifical local variables for each of the members.
   3206       //
   3207       // FIXME: Remove this code as soon as GDB supports this.
   3208       // The debug info verifier in LLVM operates based on the assumption that a
   3209       // variable has the same size as its storage and we had to disable the check
   3210       // for artificial variables.
   3211       for (const auto *Field : RD->fields()) {
   3212         llvm::DIType *FieldTy = getOrCreateType(Field->getType(), Unit);
   3213         StringRef FieldName = Field->getName();
   3214 
   3215         // Ignore unnamed fields. Do not ignore unnamed records.
   3216         if (FieldName.empty() && !isa<RecordType>(Field->getType()))
   3217           continue;
   3218 
   3219         // Use VarDecl's Tag, Scope and Line number.
   3220         auto *D = DBuilder.createAutoVariable(
   3221             Scope, FieldName, Unit, Line, FieldTy, CGM.getLangOpts().Optimize,
   3222             Flags | llvm::DINode::FlagArtificial);
   3223 
   3224         // Insert an llvm.dbg.declare into the current block.
   3225         DBuilder.insertDeclare(Storage, D, DBuilder.createExpression(Expr),
   3226                                llvm::DebugLoc::get(Line, Column, Scope),
   3227                                Builder.GetInsertBlock());
   3228       }
   3229     }
   3230   }
   3231 
   3232   // Create the descriptor for the variable.
   3233   auto *D =
   3234       ArgNo
   3235           ? DBuilder.createParameterVariable(Scope, Name, *ArgNo, Unit, Line,
   3236                                              Ty, CGM.getLangOpts().Optimize,
   3237                                              Flags)
   3238           : DBuilder.createAutoVariable(Scope, Name, Unit, Line, Ty,
   3239                                         CGM.getLangOpts().Optimize, Flags);
   3240 
   3241   // Insert an llvm.dbg.declare into the current block.
   3242   DBuilder.insertDeclare(Storage, D, DBuilder.createExpression(Expr),
   3243                          llvm::DebugLoc::get(Line, Column, Scope),
   3244                          Builder.GetInsertBlock());
   3245 }
   3246 
   3247 void CGDebugInfo::EmitDeclareOfAutoVariable(const VarDecl *VD,
   3248                                             llvm::Value *Storage,
   3249                                             CGBuilderTy &Builder) {
   3250   assert(DebugKind >= codegenoptions::LimitedDebugInfo);
   3251   EmitDeclare(VD, Storage, llvm::None, Builder);
   3252 }
   3253 
   3254 llvm::DIType *CGDebugInfo::CreateSelfType(const QualType &QualTy,
   3255                                           llvm::DIType *Ty) {
   3256   llvm::DIType *CachedTy = getTypeOrNull(QualTy);
   3257   if (CachedTy)
   3258     Ty = CachedTy;
   3259   return DBuilder.createObjectPointerType(Ty);
   3260 }
   3261 
   3262 void CGDebugInfo::EmitDeclareOfBlockDeclRefVariable(
   3263     const VarDecl *VD, llvm::Value *Storage, CGBuilderTy &Builder,
   3264     const CGBlockInfo &blockInfo, llvm::Instruction *InsertPoint) {
   3265   assert(DebugKind >= codegenoptions::LimitedDebugInfo);
   3266   assert(!LexicalBlockStack.empty() && "Region stack mismatch, stack empty!");
   3267 
   3268   if (Builder.GetInsertBlock() == nullptr)
   3269     return;
   3270   if (VD->hasAttr<NoDebugAttr>())
   3271     return;
   3272 
   3273   bool isByRef = VD->hasAttr<BlocksAttr>();
   3274 
   3275   uint64_t XOffset = 0;
   3276   llvm::DIFile *Unit = getOrCreateFile(VD->getLocation());
   3277   llvm::DIType *Ty;
   3278   if (isByRef)
   3279     Ty = EmitTypeForVarWithBlocksAttr(VD, &XOffset);
   3280   else
   3281     Ty = getOrCreateType(VD->getType(), Unit);
   3282 
   3283   // Self is passed along as an implicit non-arg variable in a
   3284   // block. Mark it as the object pointer.
   3285   if (isa<ImplicitParamDecl>(VD) && VD->getName() == "self")
   3286     Ty = CreateSelfType(VD->getType(), Ty);
   3287 
   3288   // Get location information.
   3289   unsigned Line = getLineNumber(VD->getLocation());
   3290   unsigned Column = getColumnNumber(VD->getLocation());
   3291 
   3292   const llvm::DataLayout &target = CGM.getDataLayout();
   3293 
   3294   CharUnits offset = CharUnits::fromQuantity(
   3295       target.getStructLayout(blockInfo.StructureType)
   3296           ->getElementOffset(blockInfo.getCapture(VD).getIndex()));
   3297 
   3298   SmallVector<int64_t, 9> addr;
   3299   if (isa<llvm::AllocaInst>(Storage))
   3300     addr.push_back(llvm::dwarf::DW_OP_deref);
   3301   addr.push_back(llvm::dwarf::DW_OP_plus);
   3302   addr.push_back(offset.getQuantity());
   3303   if (isByRef) {
   3304     addr.push_back(llvm::dwarf::DW_OP_deref);
   3305     addr.push_back(llvm::dwarf::DW_OP_plus);
   3306     // offset of __forwarding field
   3307     offset =
   3308         CGM.getContext().toCharUnitsFromBits(target.getPointerSizeInBits(0));
   3309     addr.push_back(offset.getQuantity());
   3310     addr.push_back(llvm::dwarf::DW_OP_deref);
   3311     addr.push_back(llvm::dwarf::DW_OP_plus);
   3312     // offset of x field
   3313     offset = CGM.getContext().toCharUnitsFromBits(XOffset);
   3314     addr.push_back(offset.getQuantity());
   3315   }
   3316 
   3317   // Create the descriptor for the variable.
   3318   auto *D = DBuilder.createAutoVariable(
   3319       cast<llvm::DILocalScope>(LexicalBlockStack.back()), VD->getName(), Unit,
   3320       Line, Ty);
   3321 
   3322   // Insert an llvm.dbg.declare into the current block.
   3323   auto DL = llvm::DebugLoc::get(Line, Column, LexicalBlockStack.back());
   3324   if (InsertPoint)
   3325     DBuilder.insertDeclare(Storage, D, DBuilder.createExpression(addr), DL,
   3326                            InsertPoint);
   3327   else
   3328     DBuilder.insertDeclare(Storage, D, DBuilder.createExpression(addr), DL,
   3329                            Builder.GetInsertBlock());
   3330 }
   3331 
   3332 void CGDebugInfo::EmitDeclareOfArgVariable(const VarDecl *VD, llvm::Value *AI,
   3333                                            unsigned ArgNo,
   3334                                            CGBuilderTy &Builder) {
   3335   assert(DebugKind >= codegenoptions::LimitedDebugInfo);
   3336   EmitDeclare(VD, AI, ArgNo, Builder);
   3337 }
   3338 
   3339 namespace {
   3340 struct BlockLayoutChunk {
   3341   uint64_t OffsetInBits;
   3342   const BlockDecl::Capture *Capture;
   3343 };
   3344 bool operator<(const BlockLayoutChunk &l, const BlockLayoutChunk &r) {
   3345   return l.OffsetInBits < r.OffsetInBits;
   3346 }
   3347 }
   3348 
   3349 void CGDebugInfo::EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
   3350                                                        llvm::Value *Arg,
   3351                                                        unsigned ArgNo,
   3352                                                        llvm::Value *LocalAddr,
   3353                                                        CGBuilderTy &Builder) {
   3354   assert(DebugKind >= codegenoptions::LimitedDebugInfo);
   3355   ASTContext &C = CGM.getContext();
   3356   const BlockDecl *blockDecl = block.getBlockDecl();
   3357 
   3358   // Collect some general information about the block's location.
   3359   SourceLocation loc = blockDecl->getCaretLocation();
   3360   llvm::DIFile *tunit = getOrCreateFile(loc);
   3361   unsigned line = getLineNumber(loc);
   3362   unsigned column = getColumnNumber(loc);
   3363 
   3364   // Build the debug-info type for the block literal.
   3365   getDeclContextDescriptor(blockDecl);
   3366 
   3367   const llvm::StructLayout *blockLayout =
   3368       CGM.getDataLayout().getStructLayout(block.StructureType);
   3369 
   3370   SmallVector<llvm::Metadata *, 16> fields;
   3371   fields.push_back(createFieldType("__isa", C.VoidPtrTy, loc, AS_public,
   3372                                    blockLayout->getElementOffsetInBits(0),
   3373                                    tunit, tunit));
   3374   fields.push_back(createFieldType("__flags", C.IntTy, loc, AS_public,
   3375                                    blockLayout->getElementOffsetInBits(1),
   3376                                    tunit, tunit));
   3377   fields.push_back(createFieldType("__reserved", C.IntTy, loc, AS_public,
   3378                                    blockLayout->getElementOffsetInBits(2),
   3379                                    tunit, tunit));
   3380   auto *FnTy = block.getBlockExpr()->getFunctionType();
   3381   auto FnPtrType = CGM.getContext().getPointerType(FnTy->desugar());
   3382   fields.push_back(createFieldType("__FuncPtr", FnPtrType, loc, AS_public,
   3383                                    blockLayout->getElementOffsetInBits(3),
   3384                                    tunit, tunit));
   3385   fields.push_back(createFieldType(
   3386       "__descriptor", C.getPointerType(block.NeedsCopyDispose
   3387                                            ? C.getBlockDescriptorExtendedType()
   3388                                            : C.getBlockDescriptorType()),
   3389       loc, AS_public, blockLayout->getElementOffsetInBits(4), tunit, tunit));
   3390 
   3391   // We want to sort the captures by offset, not because DWARF
   3392   // requires this, but because we're paranoid about debuggers.
   3393   SmallVector<BlockLayoutChunk, 8> chunks;
   3394 
   3395   // 'this' capture.
   3396   if (blockDecl->capturesCXXThis()) {
   3397     BlockLayoutChunk chunk;
   3398     chunk.OffsetInBits =
   3399         blockLayout->getElementOffsetInBits(block.CXXThisIndex);
   3400     chunk.Capture = nullptr;
   3401     chunks.push_back(chunk);
   3402   }
   3403 
   3404   // Variable captures.
   3405   for (const auto &capture : blockDecl->captures()) {
   3406     const VarDecl *variable = capture.getVariable();
   3407     const CGBlockInfo::Capture &captureInfo = block.getCapture(variable);
   3408 
   3409     // Ignore constant captures.
   3410     if (captureInfo.isConstant())
   3411       continue;
   3412 
   3413     BlockLayoutChunk chunk;
   3414     chunk.OffsetInBits =
   3415         blockLayout->getElementOffsetInBits(captureInfo.getIndex());
   3416     chunk.Capture = &capture;
   3417     chunks.push_back(chunk);
   3418   }
   3419 
   3420   // Sort by offset.
   3421   llvm::array_pod_sort(chunks.begin(), chunks.end());
   3422 
   3423   for (SmallVectorImpl<BlockLayoutChunk>::iterator i = chunks.begin(),
   3424                                                    e = chunks.end();
   3425        i != e; ++i) {
   3426     uint64_t offsetInBits = i->OffsetInBits;
   3427     const BlockDecl::Capture *capture = i->Capture;
   3428 
   3429     // If we have a null capture, this must be the C++ 'this' capture.
   3430     if (!capture) {
   3431       QualType type;
   3432       if (auto *Method =
   3433               cast_or_null<CXXMethodDecl>(blockDecl->getNonClosureContext()))
   3434         type = Method->getThisType(C);
   3435       else if (auto *RDecl = dyn_cast<CXXRecordDecl>(blockDecl->getParent()))
   3436         type = QualType(RDecl->getTypeForDecl(), 0);
   3437       else
   3438         llvm_unreachable("unexpected block declcontext");
   3439 
   3440       fields.push_back(createFieldType("this", type, loc, AS_public,
   3441                                        offsetInBits, tunit, tunit));
   3442       continue;
   3443     }
   3444 
   3445     const VarDecl *variable = capture->getVariable();
   3446     StringRef name = variable->getName();
   3447 
   3448     llvm::DIType *fieldType;
   3449     if (capture->isByRef()) {
   3450       TypeInfo PtrInfo = C.getTypeInfo(C.VoidPtrTy);
   3451 
   3452       // FIXME: this creates a second copy of this type!
   3453       uint64_t xoffset;
   3454       fieldType = EmitTypeForVarWithBlocksAttr(variable, &xoffset);
   3455       fieldType = DBuilder.createPointerType(fieldType, PtrInfo.Width);
   3456       fieldType =
   3457           DBuilder.createMemberType(tunit, name, tunit, line, PtrInfo.Width,
   3458                                     PtrInfo.Align, offsetInBits, 0, fieldType);
   3459     } else {
   3460       fieldType = createFieldType(name, variable->getType(), loc, AS_public,
   3461                                   offsetInBits, tunit, tunit);
   3462     }
   3463     fields.push_back(fieldType);
   3464   }
   3465 
   3466   SmallString<36> typeName;
   3467   llvm::raw_svector_ostream(typeName) << "__block_literal_"
   3468                                       << CGM.getUniqueBlockCount();
   3469 
   3470   llvm::DINodeArray fieldsArray = DBuilder.getOrCreateArray(fields);
   3471 
   3472   llvm::DIType *type = DBuilder.createStructType(
   3473       tunit, typeName.str(), tunit, line,
   3474       CGM.getContext().toBits(block.BlockSize),
   3475       CGM.getContext().toBits(block.BlockAlign), 0, nullptr, fieldsArray);
   3476   type = DBuilder.createPointerType(type, CGM.PointerWidthInBits);
   3477 
   3478   // Get overall information about the block.
   3479   unsigned flags = llvm::DINode::FlagArtificial;
   3480   auto *scope = cast<llvm::DILocalScope>(LexicalBlockStack.back());
   3481 
   3482   // Create the descriptor for the parameter.
   3483   auto *debugVar = DBuilder.createParameterVariable(
   3484       scope, Arg->getName(), ArgNo, tunit, line, type,
   3485       CGM.getLangOpts().Optimize, flags);
   3486 
   3487   if (LocalAddr) {
   3488     // Insert an llvm.dbg.value into the current block.
   3489     DBuilder.insertDbgValueIntrinsic(
   3490         LocalAddr, 0, debugVar, DBuilder.createExpression(),
   3491         llvm::DebugLoc::get(line, column, scope), Builder.GetInsertBlock());
   3492   }
   3493 
   3494   // Insert an llvm.dbg.declare into the current block.
   3495   DBuilder.insertDeclare(Arg, debugVar, DBuilder.createExpression(),
   3496                          llvm::DebugLoc::get(line, column, scope),
   3497                          Builder.GetInsertBlock());
   3498 }
   3499 
   3500 llvm::DIDerivedType *
   3501 CGDebugInfo::getOrCreateStaticDataMemberDeclarationOrNull(const VarDecl *D) {
   3502   if (!D->isStaticDataMember())
   3503     return nullptr;
   3504 
   3505   auto MI = StaticDataMemberCache.find(D->getCanonicalDecl());
   3506   if (MI != StaticDataMemberCache.end()) {
   3507     assert(MI->second && "Static data member declaration should still exist");
   3508     return MI->second;
   3509   }
   3510 
   3511   // If the member wasn't found in the cache, lazily construct and add it to the
   3512   // type (used when a limited form of the type is emitted).
   3513   auto DC = D->getDeclContext();
   3514   auto *Ctxt = cast<llvm::DICompositeType>(getDeclContextDescriptor(D));
   3515   return CreateRecordStaticField(D, Ctxt, cast<RecordDecl>(DC));
   3516 }
   3517 
   3518 llvm::DIGlobalVariable *CGDebugInfo::CollectAnonRecordDecls(
   3519     const RecordDecl *RD, llvm::DIFile *Unit, unsigned LineNo,
   3520     StringRef LinkageName, llvm::GlobalVariable *Var, llvm::DIScope *DContext) {
   3521   llvm::DIGlobalVariable *GV = nullptr;
   3522 
   3523   for (const auto *Field : RD->fields()) {
   3524     llvm::DIType *FieldTy = getOrCreateType(Field->getType(), Unit);
   3525     StringRef FieldName = Field->getName();
   3526 
   3527     // Ignore unnamed fields, but recurse into anonymous records.
   3528     if (FieldName.empty()) {
   3529       const RecordType *RT = dyn_cast<RecordType>(Field->getType());
   3530       if (RT)
   3531         GV = CollectAnonRecordDecls(RT->getDecl(), Unit, LineNo, LinkageName,
   3532                                     Var, DContext);
   3533       continue;
   3534     }
   3535     // Use VarDecl's Tag, Scope and Line number.
   3536     GV = DBuilder.createGlobalVariable(DContext, FieldName, LinkageName, Unit,
   3537                                        LineNo, FieldTy,
   3538                                        Var->hasLocalLinkage(), Var, nullptr);
   3539   }
   3540   return GV;
   3541 }
   3542 
   3543 void CGDebugInfo::EmitGlobalVariable(llvm::GlobalVariable *Var,
   3544                                      const VarDecl *D) {
   3545   assert(DebugKind >= codegenoptions::LimitedDebugInfo);
   3546   if (D->hasAttr<NoDebugAttr>())
   3547     return;
   3548   // Create global variable debug descriptor.
   3549   llvm::DIFile *Unit = nullptr;
   3550   llvm::DIScope *DContext = nullptr;
   3551   unsigned LineNo;
   3552   StringRef DeclName, LinkageName;
   3553   QualType T;
   3554   collectVarDeclProps(D, Unit, LineNo, T, DeclName, LinkageName, DContext);
   3555 
   3556   // Attempt to store one global variable for the declaration - even if we
   3557   // emit a lot of fields.
   3558   llvm::DIGlobalVariable *GV = nullptr;
   3559 
   3560   // If this is an anonymous union then we'll want to emit a global
   3561   // variable for each member of the anonymous union so that it's possible
   3562   // to find the name of any field in the union.
   3563   if (T->isUnionType() && DeclName.empty()) {
   3564     const RecordDecl *RD = T->castAs<RecordType>()->getDecl();
   3565     assert(RD->isAnonymousStructOrUnion() &&
   3566            "unnamed non-anonymous struct or union?");
   3567     GV = CollectAnonRecordDecls(RD, Unit, LineNo, LinkageName, Var, DContext);
   3568   } else {
   3569     GV = DBuilder.createGlobalVariable(
   3570         DContext, DeclName, LinkageName, Unit, LineNo, getOrCreateType(T, Unit),
   3571         Var->hasLocalLinkage(), Var,
   3572         getOrCreateStaticDataMemberDeclarationOrNull(D));
   3573   }
   3574   DeclCache[D->getCanonicalDecl()].reset(static_cast<llvm::Metadata *>(GV));
   3575 }
   3576 
   3577 void CGDebugInfo::EmitGlobalVariable(const ValueDecl *VD,
   3578                                      llvm::Constant *Init) {
   3579   assert(DebugKind >= codegenoptions::LimitedDebugInfo);
   3580   if (VD->hasAttr<NoDebugAttr>())
   3581     return;
   3582   // Create the descriptor for the variable.
   3583   llvm::DIFile *Unit = getOrCreateFile(VD->getLocation());
   3584   StringRef Name = VD->getName();
   3585   llvm::DIType *Ty = getOrCreateType(VD->getType(), Unit);
   3586   if (const EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(VD)) {
   3587     const EnumDecl *ED = cast<EnumDecl>(ECD->getDeclContext());
   3588     assert(isa<EnumType>(ED->getTypeForDecl()) && "Enum without EnumType?");
   3589     Ty = getOrCreateType(QualType(ED->getTypeForDecl(), 0), Unit);
   3590   }
   3591   // Do not use global variables for enums.
   3592   //
   3593   // FIXME: why not?
   3594   if (Ty->getTag() == llvm::dwarf::DW_TAG_enumeration_type)
   3595     return;
   3596   // Do not emit separate definitions for function local const/statics.
   3597   if (isa<FunctionDecl>(VD->getDeclContext()))
   3598     return;
   3599   VD = cast<ValueDecl>(VD->getCanonicalDecl());
   3600   auto *VarD = cast<VarDecl>(VD);
   3601   if (VarD->isStaticDataMember()) {
   3602     auto *RD = cast<RecordDecl>(VarD->getDeclContext());
   3603     getDeclContextDescriptor(VarD);
   3604     // Ensure that the type is retained even though it's otherwise unreferenced.
   3605     //
   3606     // FIXME: This is probably unnecessary, since Ty should reference RD
   3607     // through its scope.
   3608     RetainedTypes.push_back(
   3609         CGM.getContext().getRecordType(RD).getAsOpaquePtr());
   3610     return;
   3611   }
   3612 
   3613   llvm::DIScope *DContext = getDeclContextDescriptor(VD);
   3614 
   3615   auto &GV = DeclCache[VD];
   3616   if (GV)
   3617     return;
   3618   GV.reset(DBuilder.createGlobalVariable(
   3619       DContext, Name, StringRef(), Unit, getLineNumber(VD->getLocation()), Ty,
   3620       true, Init, getOrCreateStaticDataMemberDeclarationOrNull(VarD)));
   3621 }
   3622 
   3623 llvm::DIScope *CGDebugInfo::getCurrentContextDescriptor(const Decl *D) {
   3624   if (!LexicalBlockStack.empty())
   3625     return LexicalBlockStack.back();
   3626   llvm::DIScope *Mod = getParentModuleOrNull(D);
   3627   return getContextDescriptor(D, Mod ? Mod : TheCU);
   3628 }
   3629 
   3630 void CGDebugInfo::EmitUsingDirective(const UsingDirectiveDecl &UD) {
   3631   if (CGM.getCodeGenOpts().getDebugInfo() < codegenoptions::LimitedDebugInfo)
   3632     return;
   3633   const NamespaceDecl *NSDecl = UD.getNominatedNamespace();
   3634   if (!NSDecl->isAnonymousNamespace() ||
   3635       CGM.getCodeGenOpts().DebugExplicitImport) {
   3636     DBuilder.createImportedModule(
   3637         getCurrentContextDescriptor(cast<Decl>(UD.getDeclContext())),
   3638         getOrCreateNameSpace(NSDecl),
   3639         getLineNumber(UD.getLocation()));
   3640   }
   3641 }
   3642 
   3643 void CGDebugInfo::EmitUsingDecl(const UsingDecl &UD) {
   3644   if (CGM.getCodeGenOpts().getDebugInfo() < codegenoptions::LimitedDebugInfo)
   3645     return;
   3646   assert(UD.shadow_size() &&
   3647          "We shouldn't be codegening an invalid UsingDecl containing no decls");
   3648   // Emitting one decl is sufficient - debuggers can detect that this is an
   3649   // overloaded name & provide lookup for all the overloads.
   3650   const UsingShadowDecl &USD = **UD.shadow_begin();
   3651   if (llvm::DINode *Target =
   3652           getDeclarationOrDefinition(USD.getUnderlyingDecl()))
   3653     DBuilder.createImportedDeclaration(
   3654         getCurrentContextDescriptor(cast<Decl>(USD.getDeclContext())), Target,
   3655         getLineNumber(USD.getLocation()));
   3656 }
   3657 
   3658 void CGDebugInfo::EmitImportDecl(const ImportDecl &ID) {
   3659   if (CGM.getCodeGenOpts().getDebuggerTuning() != llvm::DebuggerKind::LLDB)
   3660     return;
   3661   if (Module *M = ID.getImportedModule()) {
   3662     auto Info = ExternalASTSource::ASTSourceDescriptor(*M);
   3663     DBuilder.createImportedDeclaration(
   3664         getCurrentContextDescriptor(cast<Decl>(ID.getDeclContext())),
   3665         getOrCreateModuleRef(Info, DebugTypeExtRefs),
   3666         getLineNumber(ID.getLocation()));
   3667   }
   3668 }
   3669 
   3670 llvm::DIImportedEntity *
   3671 CGDebugInfo::EmitNamespaceAlias(const NamespaceAliasDecl &NA) {
   3672   if (CGM.getCodeGenOpts().getDebugInfo() < codegenoptions::LimitedDebugInfo)
   3673     return nullptr;
   3674   auto &VH = NamespaceAliasCache[&NA];
   3675   if (VH)
   3676     return cast<llvm::DIImportedEntity>(VH);
   3677   llvm::DIImportedEntity *R;
   3678   if (const NamespaceAliasDecl *Underlying =
   3679           dyn_cast<NamespaceAliasDecl>(NA.getAliasedNamespace()))
   3680     // This could cache & dedup here rather than relying on metadata deduping.
   3681     R = DBuilder.createImportedDeclaration(
   3682         getCurrentContextDescriptor(cast<Decl>(NA.getDeclContext())),
   3683         EmitNamespaceAlias(*Underlying), getLineNumber(NA.getLocation()),
   3684         NA.getName());
   3685   else
   3686     R = DBuilder.createImportedDeclaration(
   3687         getCurrentContextDescriptor(cast<Decl>(NA.getDeclContext())),
   3688         getOrCreateNameSpace(cast<NamespaceDecl>(NA.getAliasedNamespace())),
   3689         getLineNumber(NA.getLocation()), NA.getName());
   3690   VH.reset(R);
   3691   return R;
   3692 }
   3693 
   3694 llvm::DINamespace *
   3695 CGDebugInfo::getOrCreateNameSpace(const NamespaceDecl *NSDecl) {
   3696   NSDecl = NSDecl->getCanonicalDecl();
   3697   auto I = NameSpaceCache.find(NSDecl);
   3698   if (I != NameSpaceCache.end())
   3699     return cast<llvm::DINamespace>(I->second);
   3700 
   3701   unsigned LineNo = getLineNumber(NSDecl->getLocation());
   3702   llvm::DIFile *FileD = getOrCreateFile(NSDecl->getLocation());
   3703   llvm::DIScope *Context = getDeclContextDescriptor(NSDecl);
   3704   llvm::DINamespace *NS =
   3705       DBuilder.createNameSpace(Context, NSDecl->getName(), FileD, LineNo);
   3706   NameSpaceCache[NSDecl].reset(NS);
   3707   return NS;
   3708 }
   3709 
   3710 void CGDebugInfo::setDwoId(uint64_t Signature) {
   3711   assert(TheCU && "no main compile unit");
   3712   TheCU->setDWOId(Signature);
   3713 }
   3714 
   3715 
   3716 void CGDebugInfo::finalize() {
   3717   // Creating types might create further types - invalidating the current
   3718   // element and the size(), so don't cache/reference them.
   3719   for (size_t i = 0; i != ObjCInterfaceCache.size(); ++i) {
   3720     ObjCInterfaceCacheEntry E = ObjCInterfaceCache[i];
   3721     llvm::DIType *Ty = E.Type->getDecl()->getDefinition()
   3722                            ? CreateTypeDefinition(E.Type, E.Unit)
   3723                            : E.Decl;
   3724     DBuilder.replaceTemporary(llvm::TempDIType(E.Decl), Ty);
   3725   }
   3726 
   3727   for (auto p : ReplaceMap) {
   3728     assert(p.second);
   3729     auto *Ty = cast<llvm::DIType>(p.second);
   3730     assert(Ty->isForwardDecl());
   3731 
   3732     auto it = TypeCache.find(p.first);
   3733     assert(it != TypeCache.end());
   3734     assert(it->second);
   3735 
   3736     DBuilder.replaceTemporary(llvm::TempDIType(Ty),
   3737                               cast<llvm::DIType>(it->second));
   3738   }
   3739 
   3740   for (const auto &p : FwdDeclReplaceMap) {
   3741     assert(p.second);
   3742     llvm::TempMDNode FwdDecl(cast<llvm::MDNode>(p.second));
   3743     llvm::Metadata *Repl;
   3744 
   3745     auto it = DeclCache.find(p.first);
   3746     // If there has been no definition for the declaration, call RAUW
   3747     // with ourselves, that will destroy the temporary MDNode and
   3748     // replace it with a standard one, avoiding leaking memory.
   3749     if (it == DeclCache.end())
   3750       Repl = p.second;
   3751     else
   3752       Repl = it->second;
   3753 
   3754     DBuilder.replaceTemporary(std::move(FwdDecl), cast<llvm::MDNode>(Repl));
   3755   }
   3756 
   3757   // We keep our own list of retained types, because we need to look
   3758   // up the final type in the type cache.
   3759   for (auto &RT : RetainedTypes)
   3760     if (auto MD = TypeCache[RT])
   3761       DBuilder.retainType(cast<llvm::DIType>(MD));
   3762 
   3763   DBuilder.finalize();
   3764 }
   3765 
   3766 void CGDebugInfo::EmitExplicitCastType(QualType Ty) {
   3767   if (CGM.getCodeGenOpts().getDebugInfo() < codegenoptions::LimitedDebugInfo)
   3768     return;
   3769 
   3770   if (auto *DieTy = getOrCreateType(Ty, getOrCreateMainFile()))
   3771     // Don't ignore in case of explicit cast where it is referenced indirectly.
   3772     DBuilder.retainType(DieTy);
   3773 }
   3774